I knew someone would mention salt in the washing up liquid, when I was a poor apprentice still living at home my RD250 would get washed every week for two years with whatever washing up liquid I found in my mums kitchen, never did it any harm.I think you would have to leave your bike soaking in neat washing up liquid for years for any effect to be noticed.
I used All Year Biker to do the work.Thorough clean, shampoo, ACF 50 pressure misted, wax to paintwork and fairings. Takes about 90 minutes. £70 of my pension but well worth it. Ready for the winter in North Wales.
Comparing using washing up liquid to smoking is a bit much!Car shampoo will leave a slight coating a wax but it has to be a very very small amout otherwise it would leave your seat, brake discs etc with a coating of wax on , not a good idea.
I used to use white parafin for degreasing but find it difficult to get around here, and more to point its become expensive. I