| Some people say TSP is a good "degreaser", which is total
| misinformation.

You seem to have very strong feelings
about TSP, for some reason. It may not be fair to
blame it for all past misconceptions that anyone
has had.

It's not a degreaser, but it will dissolve oils, like
skin oil left on woodwork, which can inhibit paint
bonding. It's mainly a very good surfactant that
will easily wipe away the black grime that collects
on woodwork over time. TSP was used at one time
in laundry detergent.

The purpose is not to "etch" the old finish.
The purpose is to clean residues off painted surfaces
without leaving a soap film. But cleaning with TSP
requires hot water. Maybe you've used it with cold
water or lukewarm water? If you use it with very hot
water (and you should wear gloves because it's a
strong alkali) it's a very aggressive cleaner.

If I couldn't get TSP for paint prep I'd use non-sudsing
ammonia. I *would not* use anything like Mr. Clean that
sudses.