How to clean a Quran Mushaf when a cockroach went over it?

Yesternight, I saw a cockroach walked on top of my Quran. It walked on top of only the outside cover and didn't go inside.It was the large American cockroach type. I read online that insects which have a pure origin ( ie they come from a pure place such as trees, ) are pure, while insects with an impure origin ( ie they come from dirty places such as sewers, toilets ) are impure. I think the cockroach must be impure, because I have seen these type of cockroahces in the sewer and the bathroom. So what should be done to clean the Quran ? Should I wipe it with a tissue or wipe it with tissue+water ?