I got a syringe at a medical supply store and used lemon juice (not from concentrate) and injected into the stem (about 1 mL) and it was gone in 2 days. You have to catch it while it's extended and move fast, it retracts rather quickly when you stab it.
My tanks: 120 Reef w/L2 Algae Scrubber, 60 Reef Pond w/floating Algae Scrubber, 40 Breeder Reef w/L2 UAS Tester Algae Scrubber
I maintain: 144 SW Reef w/L2 Algae Scrubber | 200 SW Reef w/L4 Algae Scrubber
Special knowledge: Algae Scrubbers, Acrylic Fabrication