You can only rub the collar by hand, because 502 glue is brittle after it dries, and it will break and fall off if you rub it hard. Otherwise, you should use a solvent called "acetone" to dissolve it. Drop acetone on the contaminated part of 502 glue, and immediately clean the contaminated part with detergent (washing powder) after the glue is dissolved, but this method is not needed if it is a chemical fiber fabric. If you get it, it will be very simple. After the glue dries, soak your hands in warm water of about 30 degrees, and when the skin on your hands becomes soft and wrinkled, it will fall off as soon as you rub it.