I did the same when bleeding the system after changing my front brake hoses. Have spare calipers but cba to change so bought new nipples first and am gonna give it a bash tomorrow. Been on the car for a long time and it's been standing a good while so guess it was inevitable.
Night Blue VW Golf 7 GTD : Bianca 306 Rallye : Mini Cooper D (The Mrs')
HDi Owner for 200k/9 years
HDi Owner for 200k/9 years