There are a few steps that you can take to make sure that you aren't actually losing money when you think you are saving it. First, you want to make sure never to have your coins changed at a grocery or similar store. By doing so, you will automatically have around 10% of your money subtracted for fees.

Before you take your coins to your bank, make sure they don't charge any fees for taking money. The policy for banks varies widely. Some will charge for loose coins, but won't charge if you roll coins yourself. Find out what charges exist and if any do, consider switching banks. Credit unions are usually better at not charging fees for taking coins than banks.

If you can't find a bank that will take coins without charging you, then use coins in your everyday use. You're much better off doing this that letting them sit in a jar where they will ultimately lose money for you. You can amend money jar game to benefit your savings if this is case.

Instead of saving coins, move up to $1 bills for your money jar. In this scenario, you'll be doing exactly what you have been doing, but you'll be saving $1 bills instead of change. You don't spend any $1 bills you receive, but any coins you receive are fine to use. That means all purchases have to be made with coins or large bills ($5, $10, or $20 dollar bills). At end of day, you place all your $1 bills into your savings jar. Since banks will not charge you anything to deposit $1 bills, you avoid fees your would get for change and save even more money than with coins.

If you think that changing game will keep you from saving, another way to change coins is to take them to your local post office and use them to buy stamps out of vending machines there. By switching coins for stamps, you get 100% value for your coins which is better than paying fees to have coins switched to bills.

In end it's important to remember that coins are legal currency and you can get full face value for them by spending them a little at a time. While a large amount of coins can be troublesome, there is no reason to pay a fee to have coins deposited.