No goop wanted, desired or needed.
You need the appropriate diameter wire brush for the hand piece which should be available from Pace. Find your model on their website and then look for the parts list. Spares are available online from Techni-tool, Jensen, Kimco and many other authorized distributors. Get some tips, visi-filters and the felt filters for the desoldering tool as well.
A good cleaning, once or twice a year, while hot, is all that is needed. Same procedure for the desoldering hand piece as well but it could be a different diameter brush.