Looks like this category has been ignored for a while, or perhaps some products/suggestions simply got folded into other topics. In any case, here are a couple of products you might want to use before TSHTF:
I know everybody on this forum takes superb care of weapons — no rust or corrosion on any pocketknife, dagger, machete, or pike, let alone firearms. But what about things that are sometimes less fun to use? Garden tools, human-powered carpentry tools, etc? And sometimes, at a garage sale,swap meet, or flea market, you may find tools at a bargain price, that would be useful, if only they hadn’t become rusted shut. What to do?
As useful as WD-40 and its competitors may be, they can’t undo the rust. the best they can manage is to lightly lubricate lightly rusted parts into some semblance of movement — often not enough to free badly rusted parts. Enter (a) Gibbs Lubricant, and (b) Evapo-Rust
I’ve used them both, on different tools, at different times, both with success that no amount of WD-40 could accomplish. Gibbs Lubricant is obviously solvent/petroleum based, and a light coat left on, will protect against rust. Evapo-Rust is water based, and provided it can get into the crevices and operating clearances of a mechanism (remove/dissolve heavy grease first), actually dissolves steel/iron rust, but must be rinsed/wiped off and the piece then lubed/protected after drying. No miracles here — just practical science. But they might help.
Smaller (or larger) quantities are available online from many sellers.