If you are not selling this would be great advice, also get a "red book" and underline the low mintage and more pricey dates like the 1895-o and 1916-d, and start searching.
Cleaning coins is about the worst thing you can do, the very thought of it makes coin collectors want to puke.
Don't bother cleaning them. Some of the shiny ones may actually be uncirculated or somebody may have cleaned them already. A collector would rather buy an original, uncleaned, black barber dime than a shiny one. Trust me. It takes less effort to do nothing as well. Whatever ones are heavily worn or beat up, I would view them as mainly just bullion coins, worth the silver content in them. Each dime will have 0.07 troy oz. of silver in it, give or take a bit usually based on wear. All of these I would buy tubes for from somewhere like wizard coin supply as in the link posted above. A true roll of dimes is $5, or 50 dimes per roll. It sounds like you may need to buy a lot of tubes! Once you have the average ones sorted out and stashed in tubes, they'll be a lot easier to handle and count. Any key dates or stand out condition coins should be set aside and looked into further. They may need a nice 2x2 like an intercept shield type or maybe even sent in for grading. Hard to tell without seeing pics. Barber dimes usually have a decent premium over spot, especially depending on condition. Worn out Mercs get pretty common. Just look for the 1942 2 stamped over 1 variety and the 1916-D. Both very rare so it's unlikely there's one in there but you have to check. Oh yeah, toned coins are really hot right now so if you have any that have toned some neat colors set them aside as well. They're usually worth very large premiums these days depending on eye appeal. Sounds like quite a stash he gave you. Lucky guy.