Yep, heat gun as in paint stripper gun - or I use the little butane flamer - either works well. And like Piet says, work fast!!Dellortoman said:I wouldn't think a microwave would be the right tool for the job.
I use a hot air gun. A bit like a lady's hair dryer but with more testosterone. It'll heat bearings to "spit sizzle" temperature quite evenly.