I take the valve and lever off to be able to get at everything. I use a big wire wheel and wire cup brush in a high speed ¼ inch drill motor.
Yep about the same as I doe at least once a year. In between I use a wooden handled SS brush, like a tooth brush, to scrub things down when they look a bit undesirable.
When I put it all back together I throw a dab of the Clover lapping compound under the seat and polish it back up again. It usually stays free of drips for a really long time and when it does start to on occasion I do the above all over again.