i wouldn't do that. You could easily melt the oil-ring behind it, and that could melt into the oil-passages in your camshaft.
I'd suggest taking off the complete housing and use some wooden wegdes between that and the engine itself (not TO tight, just make sure the spark advancer is touching the cam-housing on the backside and there are a few mm's space between the camhousing and engine).
Then, screw a 6mm bolt (obviously a bit longer than the one that came out..) completely in the camshaft and hit the bolt with a hammer
gently. It will just need a little help so don't go Mr. T on it
Reason for this method is that most of the times the parts just need to snap loose with the help of some impact. Not constant force, just like an impact screwdriver.
You might consider undoing the other cam-housing aswell to be sure not to mess the rev-counter gears and also to provide a bit more play for the camshaft to slide out of the advancer.
offcourse, it's at your own risk.