Over the years I've become an advocate of NOT "waterproofing" leather sheaths. Early in my career, I did a hot wax treatment, but over time learned that for longevity, leather needs to "breathe". To that end I changed my ways to dying, and then using a leather protectant similar to shoe polish.
I can understand where you're coming from asking the questions you did...... but it's impossible to "bullet proof" either your knives or the sheaths from knuckleheaded actions (or inaction). For over a decade now, every knife that I've sold comes with "How to Care for you Knife" paperwork. Even with that, I've had many incidents where people have called me up, with all kinds of self induced issues. From tarnish/rust, to what you mentioned about "dishwashers". In most cases when it's something that I directly addressed in the paperwork, my first question is.... "Did you read the paperwork I sent with your knife?" Generally there's a dead silence for a few seconds...then a "No" follows shortly. I also offer free lifetime cleaning and sharpening to my clients. They send me their knife, with return postage, and I do the rest, but I'm always careful to indicate it's not a "rebuild" service.
Here's a short exert of what the paperwork I ship with each knife contains:
- DO NOT!
- Allow your knife to remain in a hot environment such as a dashboard or near a high source of heat.
- NEVER, NEVER, put your knife in the dishwasher (don’t laugh, a number of folks have done this and really wrecked their knife.)
- Use your knife as a pry bar, screwdriver, or as a makeshift hammer.
- Pound on the spine of the knife with a rock or other hard items.
5. Store the knife in the scabbard/sheath for extended periods of time (leather). Leather will draw any moisture that is present and will likely cause tarnish or rust to form on the steel.
Warranty: All of my knives are covered by a lifetime warranty, for as long as I am physically able to work. If there is ever a problem, contact me, and I will do everything I can to "make it right".
My warranty
DOES NOT cover the following:
1. Misuse/abuse (read the “DO NOTs” listed above)
2. Damage caused by disassembly/assembly (including lost/damaged hardware)
3. If ANY modification(s) are made to the original knife.
4. Of course common sense comes into play…use your knife as a knife, and it should last for generations.
Of course nothing works in every situation..... and each of the above points came about due to "problems" that I've encountered....... you still have to be prepared to deal with customers/clients who just pull a "bonehead", and then try to attribute it to something you didn't do right. It's just something you have deal with on a case by case basis.