FTFY. More proof that glass>plastic. You can use HCL to clean out pesky stains like salad tongs.Personally for the ease of it, I liked the hydrochloric acid (aka muriatic) idea someone else proposed. Even a dilute (easy to manage) solution and time would dissolve the PET plastic carboy.
Lol, I so want this to happen and be on video.Centrifugal force...... build a counterweighted wheel to hold the carboy. Attach a motor and spin it. Make sure the force is closing the tongs. It should slip right out, you may need to borrow a 3-phase 480V motor, but they should come out.