I usually put plenty of epoxy in the slot and a thin amount on the surface I'm putting in the hole itself. You still get some that oozes out. I have the towels standing by with the alcohol on them already also. That way I can go right into wiping off the surface when I slide it in instead of getting the towel ready after I'm done.

If you do miss some and notice it after it has started to cure you can warm it up with a heating iron and it'll come off. I have only used this "trick" before it has fully cured.

Good luck.