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You can be your own appraiser for the vast majority of these coins, and you won't be paying anyone $40+ per hour. The previous answer was pretty good - organize your coins by date and denomination, and buy a copy of "Coin Prices" magazine at the bookstore; it will contain 98% of what you have. I think your goal should be to separate out the very common items and get rid of them early, then as you gain experience, concentrate on the valuable items.
The common bulk silver coins are bringing in the general range of 12 to 14 times face value; the key here is to know which should NOT be sold as bulk silver. Similarly, wheat cents are trading at so much per roll for a general run of common dates starting in the 1920s, but you should retain for further research any in extra nice condition, even as late as the 1950s material. And yes, DO NOT clean any of them, period. I personally think that gold and silver are near a peak, at least in the near term; I plan to sell my own gold when we reach $1,050 per ounce spot price. You will be much less perplexed after you have sold off the bulk-common items and can focus on the rarities, if any. A "Coin Prices" magazine is an inexpensive way to begin sorting, although you will not necessarily achieve the "book" prices when you sell. You can also buy a copy or two of "Coin World" weekly newspaper, as well as wander around local coin shows and see what's happening in the trade. I strongly advise you NOT to tell the dealers that you have 500 pounds of inherited coins, or they will pester you to death for a quick look. Finally, if you are not willing to spend a little money and considerable time up front, you will probably not achieve very good results in the end. If you spend a year studying the market and working with coins, your final net may be as much as 1/3 higher. Good luck.