While actually at the table tennis centre I use a spray cleaner and a Butterfly sponge to wipe it off with. At home I clean with a millilitre or two of Fairy Liquid ( or whatever else the missus has bought ) and a dishwashing sponge, followed by clean water to get the detergent off then a wipe dry with a Joola sponge covered with ( imitation ! ) chamois leather. In either case, i always put rubber protectors straight on afterwards - I prefer the Stiga ones as they stick to the rubber, whereas Butterfly's version tends to fall off in the bat case if you aren't careful.