What are you trying to get done? Do you have a P90 you feel is too dark?
Yeah it's got a deep dark bottom end
Sometimes a higher resistance pot won't fix a dark guitar/pickup combination.
1 meg pots are only good for jazzmaster pickups imho
There's no reason not to try it. Is that ur ax with the fat body?
Yeah it's got a deep dark bottom end
I've used 1 megs in the neck slot of LP's. The only difference is that they add some of the uppermost treble. Doesn't impact mids & lows. Is that what you're wanting? If you've got too much low end, I'd replace one or both A5's (assuming that's what in your P-90) as they have a lot of bass. An A4 or two, or an A4/A3 pair would dial down the low end. Very easy to swap magnets in P-90's.
You could try lower tone cap value, or remove the tone pot completely, or try the de-mud mod which puts a small cap in line with the pickup hot wire to the switch or pot. I would try all those routes before even attempting a mag swap.
This! I have a 1 Meg on my Dimebucker and it is still dark and throaty, however, the highs are more crystal. I would also suggest switching the cap.