Duct tape. They now make it in clear. If you can stand the adhesive. Just keep it covered and it will die/die/die. I have been through everything to remove them. Dietary change for the better was what finally did it but these days even the Dr.s will tell you to use duct tape.
Tea tree oil works! I've used it successfully, too. The key is to put it on at least 2x/day and to keep applying it to the area for a week or two after it appears to be gone to make sure you got it all or it may try to come back.
I didn't think of the GSE but that's great to know.