clean it, simple as that. clean the galvanise away from the area that is being welded (back to bare metal) and try to weld it in a well ventilated area zinc fumes aren't good for you
Yea horrible stuff to weld ,unfourtunatly its what i seem to weld most of
grind the galvanising off as much as you can and keep your head out of the fumes .... best done outside or get a fan / fume extractor to get rid of the fumes .
I have seen people just weld away without grinding the zinc off ,but the fumes are really bad and you kinda have to burn the zinc off before you get the steel underneath .
I really like it when i have some nice new mild steel to weld