I'm sorry for your loss. Your grandmother was thoughtful to leave you a remembrance.
With all due respect, do not handle those coins with your bare hands. they are silver, & the oils from your fingers will degrade the surfaces.
You should get some 100% acetone & soak them, since you've left oil deposits on the coins. It may not show now, but soon, your prints will appear, degrading the coins. 100% acetone is relatively inexpensive (don't use nail polish remover, it has impurities that will further damage the coins). It's available at stores like WalMart & Target.
Be careful, as acetone will damage many surfaces, such as plastics, oil finished wood, most household countertops, etc. Use a glass jar, carefully place the coins inside, & cover with acetone. Close the lid tightly, & let them soak for about a week. (this will dissipate any oils you've left on the coins). (Use cotton gloves) Remove the coins, & let them air-dry. The acetone will completely evaporate in a short time (10 minutes or less...). Do not rinse in tap water, just let them dry.
You'll need some coin holders (flips) to safely store them. If you don't have a coin dealer nearby, contact me (email) through this site, & I'll be happy to send you what you need...I have plenty ...