Isopropyl Alcahol 70% or better will do the trick. Slat does not dissolve in ISO so you can add it as an abrasive.
I can see many people suggesting the two together.
DO NOT WASTE YOUR MONEY ON 420 CLEANING PRODUCTS!!!
The residue is extremely toxic and the beads, if left in any part are plastic...have fun smokin that.
Plus it leaves a funny taste in your glass for a while.
DO NOT EVER USE ZEP, CITRUS CLEANERS OR ANYTHING OTHER THAN ISO AND SALT.
ZEP is not only bad to use (residue) but it also contains Pumice which will scratch the crap out of your piece.