We spend a good deal of time concerning ourselves with finding Bigfoot foot prints and casting. That's all well and fine, but good prints can be obliterated easily and not everyone carries water and casting material into the field. If it's true that the Foots know to avoid leaving prints because of easy tracking, then it seems obvious that fingerprints might be the better route.
All one would have to do is wipe meticulously clean with a microfiber cloth - found in office supply stories - objects that are smooth and easily printed - like glass and mirrors. Leaving these baubles out to be handled, will leave behind the prints of whoever messed with them. These are rather crude instructions, but helpful -
Gathering fingerprints: Use smooth object like metal or glass. Grind graphite powder from a pencil. Use a knife to scrap it, then a coin’s edge to pulverize into powder. Lay object down – use gloves – fingers on corners and not on main surface area where prints might be. Sprinkle graphite powder very lightly. Take clear tape and set down over the print to lift it. Now, place the tape on an index card so it is protected and shows.
When it comes to gathering evidence for Bigfoot's existence, one has to ask, why? Is a plaster cast going to prove Bigfoot? Is a fingerprint going to make people jump up and say "aha"? It's good to sometimes step back and ask what your goals are in the field. Do you dream of having a show? Being the one to prove absolutely that Bigfoot exists? Or are you curious about the whys, hows, and wheres of Bigfoot? In that case, all the castings and prints in the world won't help you answer that.