Best way to clean ya nasty boiling flask??

[StoneD]

Cleaning Glassware

Sometimes the boiling flask ends up with burnt on junk, and normal cleaning methods just don’t cut it… The Grasshopper’s Guide to Clean Glassware A Chemistry Koan A Chemistry Student approached the Master and asked, “Master, how do I achieve enlightenment in Chemistry?” The Master replied, “Wash your glassware.” Introduction Clean glassware is essential in chemistry. The problem is that the tolerance for shmutz varies with the work you are doing, and sometimes a chemist does not know how im…

This may help

And they couple links in this one too