Massive Coin Stash. Need Advice.

Welcome to the forum! You've gotten great advice. I just went through this on a smaller scale. You will need a magnifier, good light, and space to sort and leave your work. I'd probably get some tubes and start tubing up your circulated silver and plastic coin flips for coins that look exceptionally nice that you want to stay that way. Sorting is one thing, but you need to keep your work sorted and safe so you can eventually move it on. Selling the sorted coins will be a whole project onto itself. Good luck!