Going to play a little devils advocate here. This was one of the latest videos that was posted on the rag company youtube channel. Around the 15 min mark Levi holds up a pluffle which clearly has some light dirt in it. Again around the 15:25 mark Yvan folds his towel and again there is some dirt on it. So there is going to be some light dirt pick up. The sponge is not going to get everything. Pre-soaking does help on the dirtier areas.