If you can, try store them offline on a "Paper Wallet" you can generate one using, *CLEARNET WARNING* BitAddress.org, but make sure you do this offline, Once you have your wallet you can send your coins over to the wallet and store them, To easily get them back online, I believe you can enter private keys onto a Blockchain wallet and then you can go ahead and send them to here with shared send to mix them up a bit. I have had good experiences in the past with paper wallets, and it's pretty easy to get them back online.