So, I've read over the years, actually a good long time ago, about the preservation of vintage leathers, the main focus of this post, and back then I sort of gave up "collecting" vintage leathers, I had a real mess going on once, a stinky, recurring mold, and dirty leathers I was too afraid or un-read on to clean. I didn't have a modern home unlike now that I could regulate the environment perfectly much past the use of dehumidifiers.
Of course, I have on order like some years ago, some "pecards" antique leather dressing, and have vintage boots, slings, some spare items. Issue number one is I don't think I made a mistake cleaning some of these items, since from experience years ago, reading other posts, some people like myself would use a luke warm water and barely detergented that water, I now used a non perfumed/allergenic laundry soap. I did wash some leather items that way, including some WW2 boots that had too much dust and some dirt layered on, and I did wash three modern-ish Swiss backpacks with the rubberized top but leather slings and bottoms(did the same with a canvas topped swiss backpack I've used extensively) which had a musty smell I needed eliminated or at least knocked down mostly, and some musty smelling and grunged up surplus austrian ranger pair of boots.
What I found some years ago is that I believe it is "okay" to do this as long as some of the "washing" is lite in nature and I apply pecards leather dressing afterwards, I've done this with modern work boots but applied hubbards boot grease or plain ole vaseline. Which brings along another "trick" I noted years ago from others, those who would apply Vaseline onto leather products claiming it had the lost oils and the waxes to hold it in. Dunno, seems the vaseline trick seems "okay" for a cheap pair of walmart work boots last month for me, I may apply it on one of my spair swiss backpacks, I mean, that pecards aint exactly cheap and I even ordered a 32 oz'er, it would be nice to know if vaseline was okay and safe for leathers, its cheap especially at the dollar store, it'll just be more risque' to buy in front of other people now that I won't be shopping with my ex-girlfriend, ha, you know how people are, they see you buying vaseline and yer single they think you are buying it for something down low or dirty, never mind if its great for chafing/sun or other burns/cheap work boots/military surplus, much less if yer shopping cart has three or more containers(that's an eyebrow raiser, ha!).
WHAT DO YOU EXPERTS KNOW. I know I would have had alot more experience, but the recurring mold and stink from leather products was destroying everything else. I'll never forget the box of "collectible turkish leather products" that arrived once, ammo pouches/slings, even a couple bayo frogs, all stinky/moldy/mostly hardened and surely they were stored with horse tack or indeed soaked up 50 years of horse sweat. I learned back then what happens to old leather if too hot a water is applied to one product, also that trying to soften hardened(I mean like it was wetted then baked in the desert sun) leather. Instead of saving it for bringing in the living room in case of jehovah's witness or mormon visitors who were bugging to "help" me after they saw I was temporarily unable to do yard work, I decided to un-stink the whole home of everything "bad" and beyond my abilities to those who needed the experience. By the way, this should interest alot of the bayo collectors, cause as we all know, like for instance older bay scabbords like some I have are leather(sure hope my pecards antique leather dressing arrives soon).
NOW, THE CANVAS ISSUE.... unsure what to rant on about other I have absolutely no idea or what to use to preserve vintage canvas, other than I've never had a whole lot of those items(but items are building up this year), though I've had some really bad dirty and moldy mosin nagant slings and oh yeah, I washed those canvas items lightly, and only some remolded back, did use some antibacterial dish liquid dish soap that seemed to keep some from not molding back(tried that trick with some cheapo yugo leather mauser slings, unsure if it was the cleaning or the antibacterial dish soap that maybe prevented re-mold, who knows, maybe the whole "anti-bacterial" thing is good). Anything too collectible I left alone, have some various collectible canvas items that are dirty sealed in vacuum pac bags, some dirty WW2 dated items till I figure out how to deal with them properly, maybe dirt and grime and mold is "collectible", in some ways it is, but if it gets into your new homes' walls/etc we're talking about loss of tens of thousands of dollars of home value here, not cool, and bad allergies run in the family especially as age progresses. Technically, I have a enfield No.4Mark1 in a dirty WW2 dated and England marked enfield canvas rifle carrier with other rifles like an idiot, just "asking for it" when it come to not wanting mold to get into the home catastrophically, but it may be mostly dirty, never washed, I got it cheap, and I was thinking about "using it", but it may be valuable, who knows, it is so hard to place value on some of these items.