Ken,
I take your point regarding the effect of your influence on the outcome.
Perhaps my own view has been influenced by many years of convinceing my clients to abandon Vaxing, Vanish, 1001, Fairy Liquid and suchlike - "If you don't know what you are doing, let well alone"
I do offer free advice over the 'phone and manage to get many out of trouble useing 'household' remedies such a white vinegar, metholated spirit, soduim bicarbonate etc., saveing them the cost of a visit and me the problem of a spot being set as a stain.
Perhaps we can agree to differ on this point.
Regards,
John.