Personal opinion is to leave the lizard to go at his own schedule.
Providing he has the correct temperatures, is fed appropriate food and and is
hydrated there should be no reason to intervene. I'm uncomfortable forcing involuntary defecation on an animal, which is what
bathing appears to do.
Bear in mind that lizards reabsorb water and salts from waste held voluntarily in their cloacas. It's known they do this at differing rates according to their
hydration needs. So to remove this inbuilt mechanism for controlling
hydration levels seems foolish - although i don't know for a fact it is harmful, i wouldn't personally want to take that risk as i'd worry a about effecting
hydration and if it puts additional internal stress on the animal - although again to reiterate, i'm not say that does happen. Likewise as it is a two way process, i don't know if forcing bowel movements effects the excretion of unwanted salts either.