You definitely need to use some sort of abrasive for cleaning.
Alcohol isn't likely going to remove the oxidized layer from
the surface.
I am lazy, so I use a Dremel roto-tool and the steel brush
attachment to give the whole board a quick polish before
doing my ironing.
What brand of laser printer are you using?
I have heard that newer laser printers use a lower-temp toner, whereas the old HP Laserjet II's (the one I have) require
a very high temperature to melt the toner.
The toner formula may have something to do with it's
ability to stick to the copper. I have not experimented
with this, so I don't know for sure.
~Rolan
--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan <stefan_trethan@g...> wrote:
>
> i have cleaned the board with alcohol, as it was quite new i guessed this would be enough. next time i
> may give it a rub with steel wool and see if it gets better.
>