Whats the best way to clean ceramic flower pots that have already been soaking and wont come off?

Whats the best way to clean Ceramic Flower Pots that have already been soaking and wont come off?

Firstly

Rinse the ceramic Flower Pot with water.

Secondly

Gently wipe the dirty place of ceramic flower Pot with wet towel.

Thirdly

Smearing toothpaste on the the surface of the flower pot, wait five minutes, and wipe gently with a wet towel.

Finally

After the dirt is wiped clean, rinse it off with clean water, and then use a dry towel to wipe clean the flower pot, so that it is not easy to have dust.