Earl: I assume no liability in the act of you using chemicals in any way!!! Hey jack...powdered creamer and sugar mixture could go wrong too!!!! Hahaha...seriously....I've tried it all....been doing the Tilex thing 1x a year for the last 5 I bet...no problems here!!! Spray...wait...hit Em with a 40 deg nozzle pressure washer ...bam! New again! I do treat them right away after that though...get a good uv protector..