I have one Question.
few days ago i imported my Paper wallet to Blockchain.info for sending some funds. after that I deleted everything about that paper wallet from my blockchain wallet including private keys too.
now the problem is now i use that same paper wallet from somewhere else.
You shoud never reuse paper wallets. Lets say you have a paperwallet with 1 BTC send to its address. If you import the privat key and spend 0.1 BTC with it, the rest has to go somewhere. Typcially a wallet uses a newly generated change address for that. Thus your paperwallet is now empty. If you have no longer access to the private key for the change address you lost 0.9 bitcoin.
So my question is if we import our paper wallet to blockchain.info can not delete from site ?
#1 import the private key
#2 spend everything
#3 send rest to a new paper wallet
#4 delete the empty blockchain.info account/key/etc.
If you are careful and know what you are doing its perfectly fine to delete a private key.