Where can you dispose your old coins?
How much do you want to get for them and how much effort do you want to put into it? Easiest ways get little or no return - Standing on the curb and waiting for the street sweeper gets immediate results, takes little effort, gives a negative return. Getting a business license, opening a shop, and selling to the public will take a long time, a great deal of work, get the highest price for the coins, and probably still lose money. The quickest way to dispose of them would be to sell them to a dealer, but get offers from three or four before selling. Any other way (except the street sweeper method) will require that you learn about the coins first, and even if going to a dealer, you will get a better offer if you know what you have and have separated the more valuable items from the "junk". Once you know what your coins are you can advertise them in the local paper. That can cost more than the coins are worth unless you place a very general ad and make several sales from it. You can sell them on eBay - not as expensive as newspaper ads and gets a larger audience but takes quite a bit of work on your part. You can also sell at a consignment auction, but if you don't have them described correctly you may not attract the right bidders. If there is a local auctioneer who handles a lot of coins, they may do a bit more to help you sort and describe them and will also get the advertising to their regular buyers. If it is a large collection, an auction house may schedule an auction of just your items. And if it is a very valuable collection, you need to contact one of the big auction houses that specialize in rare coins like Bowers & Merena in Irvine, CA, or Heritage Numismatic Auctions in Dallas, TX.
Which retailer offer to dispose of old computers and other electronic products properly to help protect the environment?
When a coin is being withdrawn from circulation, there is usually an advance notification of the withdrawal, followed by a grace period when people can get rid of these coins at their local bank. Once the grace period is over and the coins have been demonetised, the banks will no longer accept the old coins. If your coins are very old and in good condition or better, you might take them to a coin dealer.