Removing Padded Value in Decrypted Message
How you remove padding after decryption depends on how padding was added before encryption.

Typically, we design padding methods so that it is easy to figure out exactly how much padding was added; see This article for an overview.

From your question, it sounds like the encryptor is doing zero padding (that is, adding zero bytes until the next block boundary); if you can assume that the message will never end in a zero byte, then it is easy to remove.  If you can't make that assumption, it sounds like you may need to switch to another padding method; the one in RFC5652 is one common method.