best glue for resin

Dish soap and warm water. It's CMK, and I have never had a problem with their stuff having oil on it, but washing it cannot hurt.

Then use CA (superglue).

Some resins are really hard to clean. Soap and water often fails to do the job for me. I use 91% ISO alcohol. Also, you'll need to use super glue (CA) or two-part epoxy. If you are going to be putting any stress on the parts during construction, like sanding heavily or pressing them into place, I suggest using two-part epoxy. It sounds like a lot of hassle, but you can squirt a drop of each part on a piece of plastic and mix them pretty quickly. Barrett