rubber cleaning

I have a H3N which is tacky. After about 2.5 hours of straight playing the rubber lost most tackiness. Is this normal for tackiness to just disappear mid session? Or does it still have tackiness but I can’t feel it with my fingers? How can I restore this tackiness or will it happen naturally...

How do professional table tennis players clean their rubbers properly? I'm using the DHS H3 neo provincinal 40° blue sponge, and I've noticed that the tackiness wears off quite quickly. I've read a lot about boosting and different rubbers, but I haven't found a specific thread on how to clean...