Our kids, 4 and 2 and their friends love this bounce. It's the best thing ever. It was received as a gift in July and it's August now. There is mold on underside of the slide and the overhead 'pillars'. We have never left it out in the rain or set up overnight or allowed kids to go inside wet. Aside from maybe night-time dew, I don't know how this happened or what to do. The mold is on the inside and can't be wiped down.