Usually I use a small flathead screwdriver. Works amazingly well with a glass spoon.....and pretty much any glass piece.
Boiling the piece. Rubbing alcohol and salt in a bag. Heat up areas of your piece then use a bobby pin. I typically left this up to my friends. The resin was their reward.
Really the most effective tool I have found are dentist scraping tools. There are many different styles to choose from. Some with long picks to get deep inside the bowl, some with curved picks to go around corners.... or similar wax shaping tools.
^speaking of which. i advise everyone not to scrap a bowl that has broken because there could be tiny fragments of glass in the resin
I use a jewler's brush, I would use a steel wire brush if I had one. You might also try an ultrasonic cleaner without chemicals if it's a metal pipe.
++ that's similiar to what I use. The curved shape pretty much fits all my bowls perfectly. I dropped one of my favorite pieces and salvaged as much resin as I could from the innards. Smoked it all while thinking of my precious fishy pipe. RIP Fishy Pipe
i boil my peice then shove a straw through it. then let the straw dry and cut it open and scrape the straw for resin. i get like a dimed size ball.