When guys work on a pipe . Theres a few different ways to secure it . Those 'marks' you see are from the tool that holds the pipe [ as has been mentioned ] . Others use a cone made of wood , or whatever , that the chamber slides onto ... in order to hold the pipe . Theres vices and all kinds of stuff to secure a pipe . Those marks will in no way mess w/ the pipes ability to smoke properly . They are not considered flaws by rational people . It's inside the bowl .... after a few smokes , ya wont even see it . You could always sand it if it freaks ya out to much ... but why would you . It's one of those things that really dont matter .