Quote Originally Posted by Alibert View Post
They look like steam bubbles to me. Take a magnifying glass or USB microscope for a better look. Try to 'pop' them.

If steam bubbles, you need to dry your filament.

Despite the many false claims, PETG really does absorb water from the environment (as does every polymer to more or lesser degree .... ).
Heres a pic after some widdling, whats the best way to dry the filament. Its only been out of the shring wrap for two days