I was called back today for a carpet clean I did a couple of days ago: Natural coloured wool, cut-pile.
The customer was complaining of 'dark spots' all over the cleaned carpet. When I arrived I found they'd put small bits of masking tape all over their carpet, to show me where the problem dark spots were.
Examining the spots with a microscope showed that these spots were in fact naturally occurring darker wool fibres in the carpet - in other words they'd always been there!
I explained that, now the carpet was cleaner it was also lighter, but the dark bits remained dark - so they showed up more clearly than before cleaning.
They were not convinced. So I asked them if they had a bit of the carpet that would definitely not have any staining on (e.g. an old off-cut)... Which they did. And that piece also had dark spots on it. So now they were convinced!
Ah well.... live and learn
