Why do professional table tennis players occasionaly rub the part of the table that is near the net?

Question

I'm talking about the area that is near the net and the baseline. If you have watched professional table tennis matches it should be clear what I am talking about. I find it strange and I'm curious to know why they do this.

Answer 1

in addition to the dust particles of previous answer they sometimes are wiping sweat off of the table as it travels far during play.

Answer 2

In case there are dust particles that might deflect the ball. It doesn't take much.

Answer 3

Sweaty hands.

Answer 4

They do it to rub off the sweaty hand. They used to rub the baseline but nowadays more players would opt to rub at near the net.

This is because the area near the net is least likely where the ball will be landed. In table tennis, it is almost impossible to get a hit on those area as it is too near the net.