Yes, I've seen this too.
There are two ways:
1) scrape off the majority. Use the edge of another board or a steel
scraper. My toner comes of quite easily this way. Minimal residue and
toner chips can be wiped away with very little acetone.
2) use more acetone. What works well is to put a thin tissue paper on
top of the PCB and saturate that by dripping acetone on it. Let it sit
for 5 or 10 seconds, enough to soften the toner but not enough for the
scetone to evaporate, then pull the tissue away with a wiping action.
You'll be left with a smeared transfer of the artwork on the paper and
a clean board.
Either way works well for me, what doesn't work is using not enough
acetone - will lead to the smears just like on your picture. The
peculiar thing is they won't come off completely even with much more
acetone. This is strange because acetone doesn't seem to attack the
boards themselves so I don't understand the mechanism at work, I
suspect microscopic surface roughness is to blaim.
ST
On Mon, Jan 11, 2010 at 6:35 PM, nathan_h_tna <nathan_h_tna@...> wrote:
> After etching my board I cleaned it off with acetone, and although most of the toner was cleaned off, some of it smeared:
>
> http://www.roboticsguy.com/images/misc/smeared-toner.jpg
>
> What's the best way to clean the toner off the board?
>
>