Homebrew PCBs

I have been using "the" toner transfer method for about 2 years and 
produced some very good PCBs.
Until a week ago!
I had problems making the toner sticking to the copper.

After a lot of frustration I tracked the problem to the kind of 
liquid soap I used with Scotchbright pads to clean the copper.

It turned out that my wife changed the brand of liquid soap to 
one "that is kind to your skin". So it may be - but it leaves an 
invisible (oily?) film on the copper which is virtually undetectable.

Using my old liquid soap brand cured the problem.

I feel pretty silly now, but then again 20:20 hind sight always leads 
to highly accurate observations.

The moral of the story is of course - check the cleaning agent and 
don't let your wife decide the brand.

Frank