Hello Harriet; There are various types of glue used to pin insects. Some are water soluble while others dissolve in organic solvents. You can try this little routine to loosen the bugs. Place them in a closed container with a piece of paper towel soaked in...
1. Water. Or,
2. Ethyl acetate.
One or the other should soften the glue within a few minutes.
You can repin the bugs when the photography is finished.
The preferred glue for this purpose is a hotly debated subject. I use hide glue.
Harriet Harris ...... Harriet, you might consider a different approach. Photograph the insect with the pins and remove the "distracting" pin via software.----Adobe Photoshop has an "AI" feature to remove many types of distractions and fill the gap with relevant background.