Rinse with HOT water, it helps. You can add salt to the Iso as well, helps to abraid the gunk but youll need to shake it which may be too much for this piece specifically, it has some fragile looking stems.
Plus one of the salt recommendation. That thing will be good as new. If you have another piece you should probably use that for a bit while this one is soaking
I use that method for cleaning my coils on my concentrate pen. Works perfectly. I kinda hate to use that much alcohol though if I can avoid it - it's a big piece.