cleaning them will be fine, i know a few people who have winter wheels, and they have them more so that if there was a incident were they skidded into a curb or were driving in really deep snow they couldnt curb the wheels.
last year i left my wheels all winter with out cleaning them and they were fine
this year however after getting some tt comps i shal be cleaning them and waxing them every weekend or so, unless i can find some were selling cheep winter tyres in which case i shal purchase some, stick my old alloys back on and store the tt comps untill next year