In recent months we have been using two shampoo polishes. These were 1001 and Johnson's, obtainable in a 10-wash tin or in individual sachets. To choose between them would be almost impossible, but it was easier to decide whether shampoo polishes work at all when the car was washed twice a week for a period, the polish built up and stains didn't get a chance to develop. If, however, as happened on the white paint of our Porsche, it was left for a week or so, then stains appeared, which didn't come off with the wash, and in time the polish builds up over the stain; so for the regular washer this is a time saver.
After having cleaned the built-up stains off with Simoniz cleaner, which removes almost any mark, an American liquid polish called Westleys, and which is rather expensive in England, was used. This goes on easily and for a high finish polish buffs up very easily. The secret seems to be to use plenty of clean polishing cloths and a really good surface can be obtained without developing "housemaid's elbow."