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How "not' to kill mold spores, and the right way

22K views 51 replies 24 participants last post by  Itsawhatchamacallit 
#1 ·


This is a tough thread to write and a super-cautionary tale!:(

I recently bought an Artillery holster in nice shape at a good price,
1917 marked, belt converted, nice supple leather. Had Jerry the holster man take a look at it before I bought it, looked fine, except for some white mold spores.

Asked the best way to "kill" the spores and got instructions:

"Heat oven to 350 degrees, put holster on a cookie sheet and put in oven at 350 for 5 minutes, cut off the heat. Leave in for one hour and take out. Mold will be dead and no harm to the holster."

Simple, just be aware that it may smell up the kitchen a little.

So me, I think well I'll take care of that and wrap it in foil to keep the odor down and prevent it drying out to boot.

WRONG!!


What I did was "boill" the leather , then dry it out! It was shunk, twisted, and hard as a rock, in short RUINED! Only salvageable
piece was the brass stud for the cleaning rod flap.


I'm not posting this so anyone can tell me I was stupid or dumb or anything of the sort, I have already beat myself up enough.

This is to help someone else avoid a potential disaster!


Added by Jerry, lugerholsterrepair:

I asked Don to post this for the reason he has stated..I recommend this procedure to any and all collectors who have a mold problem on leather. My Wife Ellie and I struggled for some time many years ago to find a cure/solution to some molds found on Luger holsters. After much research on mold, we concluded that if enough heat could be safely applied, the mold spores deep down in leather would be killed. We did extensive testing..with old leather parts and pieces that if ruined..would be no great loss. And ruined they were. I had this very thing happen to me when I put leather into an enclosed bag and applied heat.
What happens in an enclosure is that molecular moisture..present in a fairly sizeable quantity in a holster, escapes and condensates inside the enclosed area and turns to steam. Steam is deadly to leather. Just as it is to living skin. I can't tell you the chemical or physical properties that cause it to change..I only know the result as you can see from Don's photo's. Disaster on a grand scale.

The basic heat treatment WITH NO enclosure other than the oven..works with NO HARM to leather. I have done it more times than i can remember. 350 F. for the short period recommended will NOT dry out leather. It often has the opposite effect. Moving and distributing any applications of whatever has been put onto it over the years. I have NEVER had a bad effect yet by placing a holster in an oven at 350, laying on a cookie sheet with no covering whatever.
One caveat comes to mind as I write this..LEATHER. I have NO experience with this procedure for ERSATZ holsters or say, Japanese CANVAS holsters. LEATHER ONLY.
So to clarify this procedure..that I have used with great success to kill some types of mold and completely erase the white mold flowers from the surface.

Preheat oven to 350 F. Place your leather item on a foil covered cookie sheet..foil is just to make the Wife happy. If you are a bachelor a plain cookie sheet is fine. I have never had anything drip off.
Place your cookie sheet with exposed leather on a middle rack. I sometimes use a wooden stick to prop open a Luger top so the heat can reach full temperature inside.
I usually wait a few minutes to make sure the oven has achieved 350 after opening the door..then TURN THE OVEN OFF! Let your leather lay..an hour is usually long enough. The oven will gradually cool but the leather will have reached killing temps through and through. I have found no harm to studs or buckles..One benefit has been to take out your leather while still warm and verdegris will easily wipe off with a terry rag.
As horrible as this experience has been for Don and even myself..I encouraged Don to help us all with an explanation of what can happen..these photo's are tragic..but there IS an explination of why it happened and we should avoid this, learn from this. I wouldn't FEAR my mold killing procedure..just DO NOT ENCLOSE the leather, leave it EXPOSED.
Thanks Don, I know it's a platitude..but your loss results in our gain. Learning is an ongoing endeavor.


Before and after disaster:
 
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#7 ·
Sorry to hear this loss... 350 degrees!! That the temperature we recharge silicon dehumidifier box. Those tiny silicon pellets become so hot that hand cannot touch even 10 minutes after the box was pulled out of oven.... no wonder leather could be "cooked" at this temperature.
 
#8 ·
Alvin

Reread the first post, especially about the holster being wrapped in foil. It wasn't the heat that destroyed the holster, it was the trapped moisture that was turned to steam.

I'm very sorry to see a nice holster destroyed, but appreciate Don and Jerry making it clear what will happen if you heat leather when it's wrapped or otherwise enclosed. Without this object lesson, I might very well have made the same mistake.
 
#13 ·
Don, what can I say other than I am so sorry to see what has happend to you and your holster. How brave and nice of you to share your mishap, hope for many of us it will be a lesson well learned and remembered.
Peter
 
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#15 ·
99% of common mold spores will die at a sustained 150°F for ~20 mins.

NOTE: This is merely my opinion and I am NOT recommending anyone bake their leather goods at any temperature.
Any you know this how? Reference please.
 
#16 ·
My dad was a flight test engineer and he said you always learn lessons more deeply from failure than success; the before and after photos on this holster are an excellent lesson, although it is very unfortunate a member experienced such misfortune.

As far as the various "alternatives" then offered by others, I appreciate the intent to help and participate, but you'd have to convince me that you had expertise on Jerry's level re: holsters before I would go with your method vs. his.
 
#20 ·
Like 'p08man', I've had great results using a 50-50 white vinegar and water solution to kill mold. 20 years ago I obtained a WW2 German seatpack parachute rig,
complete with full harness straps and fittings. It smelled extremely strong of mold when I got it, so I douched it down with a spray bottle of the vinegar solution
and let it fully dry. I then repeated the spray wetting, saturating the web harness well again. After drying, the mold smell was gone, and after a few weeks the faint vinegar smell was gone as well. That was 20 years ago and still no mold smell. I've done the same with a couple luger holsters with no white spore powder or mold smell returning, and after more than 15 years they only have that wonderful German leather smell we all love.
 
#21 ·
David, Good to know..At 350 start..likely penetration to the interior of leather is a lot less. It's my understanding mold spores are encapsulated and it takes more heat than organisims that are not encapsulated.
At any rate..In the many holsters I have subjected to this procedure..absolutely no harm has taken place. It's possible that the procedure temperature could be adjusted down somewhat..Although I fail to see why at this point. I always appreciate approaching with caution..but if the temp is high enough..with no harm and it kills a guaranteed 100% the procedure will not have to be repeated?
I have treated some holsters a half dozen times with no ill affects. Mold keeps coming back to these..I don't know why.
 
#22 ·
Thanks for your thoughts and observations, Jerry. The care of old leather items is a particularly difficult challenge. I suppose it could be worse--the preservation of old books which often have leather covers or acidic paper in addition to vulnerability to mold, staining, tears, and other woes often requires serious care and control over storage conditions.
 
#23 ·
I have tried two methods so far:
One was Jerry's older method: put the holster in the 2 gallon plastic bag, seal it and put in a pot of boiling water. Almost killed a nice Mars artillery holster that way - leather got very stiff but I was able to pull it out of the water in time so the holster suffered no other ill effects.
The second method was the vinegar solution, but even after multiple applications, some of the mold would come back after a while...
What is strange is that it is always the same holsters that continue to grow mold. The other holsters stored next to the ones affected do not get the mold... I wonder if it has anything to do with the leather treatment that the affected holsters had in the past. It is usually the oily soft leather that gets it...
 
#24 ·
If you know someone in the business, embalming chemicals are made to kill mold.

I've killed mold by evaporating a small amount of formaldehyde in a closed space.

Note, that this chemical is a carcinogen. I'm also not sure if it will make changes in leather, so approach with caution after consulting someone if you want to try this route.
 
#27 ·
actually Acetone is fairly effective for cleaning and won't hurt leather.
Bleach on the other hand is highly toxic, will discolor leather, dry it out, leave a residue and in general ruin whatever you put it on.
 
#28 ·
Recently I used a simple hair dryer. It helps to direct the heat and cool down when too warm. You can see the mold disappear. Probably not as long lasting but easy to repeat when needed. Works well on very brittle holsters.
 
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#29 ·
Gerben, Yes..That is a treatment but like you say..likely it will not penetrate deep enough to kill anything but the flowers.

I use a hotbox here in the sunny Southwest. It's a box painted black inside with a plexiglass cover. Solar oven if you will. I can pretty quickly achieve 180 degrees F on a sunny day. This will do the same as your blowdryer. Erase the flowers but I still suspect the temp is too low to penetrate very well and actually have an effect on the encapsulated spores. On the plus side, I have left holsters in for several hours..Hoping it will beat back mold for a longer time.
 
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