Not adviseable to wash car outside..some car wash center use dish washer (green liquid) to wash your car as it is very cheap. That really pain as it strip off the laquer layer fr the body..Per -bottle can get it ard Rm1.00 as they import in bulk from china...furthermore, the cloth or sponge they use to rub your car sometimes drop to the floor, upon pick it up, the small stone & sand are trap on the cloth without been cleaned & continoulsy rubbing your car body..that why you can see lots of car that used send to wash outside got so many swirlllll..especially on those dark color car..