I have used these many times. It uses just water pressure too clean the car. At first I was even unsure about it, but after doiing so I was SOLD!!! If I cant do it myself due too cold weather I take it too the one in the town that I live in and let it do the work.
yeah thats very true about any of those, but if you go to your local auto store they sell bug n tar remover, of which I have had too use due too long summer drives where my bummmer because a bug killer. THe only thing that got all that off was bug remover, unless i wanted to remove the paint with the brush or mitt.