"Excess glue" refers to having more glue than is needed or necessary in a particular situation. It means having too much glue, which can be messy, wasteful, or cause problems. Full definition
Modifications just involve removal of unnecessary brackets and the removal of excess glue (to reduce weight — believe it or not) plus the addition of a still steel roll cage. (astonmartins.com)
Wipe excess glue off bare wood for stained projects, as dried glue will not take stain. (ana-white.com)