I just purchased a pair of CryoBit cards and it occurred to me that, while I know how to send money to a cold storage wallet, I am not exactly sure how to send money out. I assume I import the private key into an online wallet, like BlockChain, and then do a full sweep to another address in the BlockChain wallet.
But if I import the CryoBit private key doesn't that expose the private key on my CryoBit card, reducing the full trust of that card? I've read on other answers that once a cold storage private key is imported into an online wallet that wallet should never be used again... At $30 per CryoBit card that seems like an expensive waste to discard the card after one use.
Also, if I do import the private key on the CryoBit card into BlockChain, do I have to do a full sweep or can I just send some of the CryoBit private key funds out?
Say for example I have $1000 on my CryoBit card and I import the private key into BlockChain. Then I send $500 to an external address leaving $500 on the CryoBit address. Then to clean up the cold storage I delete the private key from BlockChain. Will I still have a trustworthy cold storage wallet in CryoBit with the remaining $500?