Best way to clean ya nasty boiling flask??

[cyclopath]

I like the approach shared by @23extracts…

Cleaning glass after pesticide contamination

I went and bought a large kiln. I remove as much of the waste as possible, flush with ethanol. Then I put it it in my oven. Let it slowly ramp up to 565c. It’s hold that temp for 2 hours then slowly cools off. In the morning I have nice clean glass.

…but still haven’t talked the boss in to handing over the kiln that’s been sitting in his shop, unused, for the last five years.