From FB group Building Transistor Radios, Aug 6
This also happens with the meter movements of old analog meters. The iron particles get into the magnet assembly and stop the coil from moving. The only way I’ve found that gets rid of the iron particles is to very gently put a thin piece of steel into the gap and get the particles to stick to it then pull it out. This may have to be one particle at a time, and may take a long time with many particles. You can’t use a magnet because that can demagnetize the speaker magnet. A nonmagnetic tweezers is helpful. One thing I haven’t tried is adhesive tape. But tape could damage a meter movement. A speaker might be less delicate and the tape might remove many particles at a time.
