The Emperor, Darth Vader, Mon Mothma, Obi-Wan Kenobi, Yoda and possibly others (haven't tested all) can remove corruption; drag them onto the "remove corruption" slot (this will cost you about 1500 credits though).
Interesting to note that sometimes the Emperor seem to be doing the "repove corruption" thingy automatically w/o costing any $$. The cleansing count down seem to be on whenever the emperor is on the planet.