Are you talking about the surface mount ones or the through hole ones?
For the through holes ones, it's pretty easy. First just use a solder sucker on each pin and if it still sticks, rock it till it breaks free.
Interesting, that is what used to do until I got tired of fighting with the little bit of solder left but held on hard. I found it very hard to melt that little bit of remaining solder particularly on multi-layered boards. I might have been doing something wrong.
You will end up pulling the PCB pads off if you torque it too much sideways
I actually had that happened when I cut a (non-SMD, 1/2-1watt) resistor - I did not cut the legs (can't reach) but cut the resistor in the middle using a wire cutter. The cutting introduced some pulling force and that pulled the PCB trace right off the board.
If you can totally sacrifice the pot, you can take the hot tip of the iron and stick it into the side of the plastic and heat the lead from the inside.
This is a fine idea! I consider the pot dead since the screw is slipping and can't adjust anymore (thus the planned replacement). For this job, this just may be best - no torque/pull introduced by cutting. I have a dead (open belly) soldering iron that I am about to throw out. I use that iron to melt the pot (who cares about plastic left over on a iron I am about to throw out). Once the inside is exposed, I can separate the legs easier.
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All these are great ideas. In some ways, I am worst than beginners. My electronics experiences was when Apple was merely a fruit, and Bill Gates was Bill Who? Since then, I have done just simple "fix a broken wire" level of electronics. It has been so long since I soldered components, and some of what I do "remember" are too fussy, worst is, some I remember wrong. So I have to relearn some and unlearn some.
Thanks guys for sharing your experience.