Something like @dustsweeper but for comments that get upvoted could also help. Basically, people with not enough hive power to upvote comments send funds to an service account like dustsweeper and when you upvote a comment it adds to the vote to reach the threshold taking that from your balance in a way that can't be exploited.

I believe @dustsweeper lets you choose whether to boost your comments only or to boost all comments that you have previously voted.