The problem at this point, Di Tou had realised had nothing to do with the potency of his Void Qi, or the grime being more annoying, but rather his own refinement and ability. And of course, it also had to do with Di Tou being stubborn. If Di Tou didn't care, he could simply use Void Qi and remove everything, rock, stone, and water included, and although it would be a bit patchy, at the end, everything would indeed be gone, so there was no need to worry if any grime was left.
But what Di Tou was trying to do instead was slowly pick out the grime bit by bit, and even more ideally, do it all in a single sweep. It was a bit hard to imagine, but one could imagine it in three levels.
