I work at a hotel and have an in-ground spa. Since I have started working here two of our jets have popped off. I bought replacements(waterway poly jets) but they do not fit in the openings. I know they are the right type, I removed an existing jet and screwed in the new ones just fine. I think the threaded area of the old jet is still lodged in the opening. Is there anyway for me to get those broken pieces out without breaking concrete? Any info is much appreciated.