Absolutely, mate! Your private keys can be encoded and exported in various formats, including Base64.

However, most Bitcoin wallets use a standard called Wallet Import Format (WIF) for private keys. This format is a bit more compact and includes some error-checking data.

But sure - if you've got the technical chops to convert them into Base64 or any other format, go for it! Just remember to keep 'em safe. Losing your private keys means losing access to your coins.