I make sure I have emptied out all the powder. I cycle the measure several times, use an artist brush to sweep out the resevoir and not much else.
Like others have said, I do not want to re-season the measure. My 40 year old Uniflow’s hopper is virtually opaque from the build up of graphite on it.
I’ve never cleaned my powder measures with any solvents or cleaners once they were put in service. Cleaning off any rust preventative before measuring powder can be benificial. Lee Precision recommends running a pound or so of powder through the measure before charging cases. This helps season the inside of the powder measure. It is a good thing to do with all powder measures.
I usually store an anti static dryer sheet in new powder measures when it is not in use. After a while, when the measure is seasoned, this is not as necessary.