Pass on the brake cleaner drum. Burnout temperatures may not compare to welding temperatures, and you don't get your face in as close while doing a burnout like you would when welding, but there is a firsthand account of how sick someone got from phosgene gas when he welded metal he had cleaned with brake cleaner. Read it for yourself and then decide.
http://www.brewracingframes.com/id75.htm
No doubt that this was a very isolated incident , but with so many other suitable drums out there and readily available, this one may not be worth the risk.
Chris