Yes, you may benefit from using something like bilthamber deox gel for heavy rust deposits,
If you wire brush and chip away loose stuff then apply the gel in a thick coat and wrap with cling film to stop it drying out for a couple of days it will eat away and break down the rust, you will need to wipe it off and clean it up and re rotary wire brush it after,
It's quite time consuming/slow but is a good way of removing the rust with out taking away to much good metal around it,
If you google it you should find some good guides on how to use it