I made a multicolor print and used transparent PETG as the support interface. When the print was completed, I had tiny dots of the PETG on the outside of the print on the opposite side of where the supports are and are slightly melted to the surface. The dots are tiny and even on the print in spots that are above where any supports would be. I have no idea where these specs would come from, any help would be appreciated.
PETG can stick to the nozzle and leave a blob when crossing a wall. That’s likely what happened here IMHO. Reorienting print so that PETG-contaminated nozzle won’t cross the wall is what I sometimes do when I’m in a hurry.
The other side is calibrating the filament and making sure it’s bone dry, that also helps with it working better as a support interface.
A similar problem has been reported before. Suggest to look through the forum.