This is a potentiometer for a triac light dimmer right? You're not just going to try and burn off extra power using the potentiometer? If you are, the potentiometer almost certainly can't handle the heat.
If you are using it in a triac light dimmer, why just not make it so you can swap them out...if you were going to test them all it means you already have them all anyways...THey dont' need to be all that high quality either. If they're inaccurate but controlled by a human, the human won't care- they'll just adjust it until it's the brightness they want and not notice a thing. And how often do people adjust the light anyways? I could adjust the light 50 times a day and a crappy 10k turn potentiometer would still last 2/3 of a year.