I have a (USGI I think) fiberglass stock on my M14. When taking the GI tool out of the buttstock hole I noticed it was covered with a light tan, very fine grained "sand" despite being safe-kept. I shined a flashlight down into the two buttstock holes and see that the holes are drilled into a yellow stock filler type of material inside the buttstock. Is there a material, epoxy or some such, that I can mix up, pour into the holes and leave a thin coating on the holes to keep the yellow material from being eroded away? Something akin to the "tank cream" we use on motorcycle gas tanks?