Homebrew PCBs

What is the secret to successfuk Toner Transfer? I have been 
consitently getting only partial transfers.

I have been cleaning the copper as well as I know how. Sanding, 
ScotchBrite, and acetone.

A fer days ago I tried some test transfers on 1/16" material. After a 
couple good transfers on that material I went to the 1/32" material I 
need to use. Now I am only getting between 50% and 75% of the toner 
transfered. The part that does transfer is bonding very well.

I read one place to keep the heat on it until the paper appears 
scorched. They claimed there was no such thing a too much heat.

My iron is getting very dirty so I am now cleaning it berofe the next 
try.

Bob Macklin
Seattle, Wa.