How do I get yellow, rust or mold spots off my plastron, chest protector straps and fencing whites?
Work out which stain it is first, because each one needs a different fix, and keep chlorine bleach away from all of them. Grey, black or greenish speckles that appeared after gear sat damp in the bag are mildew. Yellow patches at the underarms, collar and chest are built-up sweat, body oil and detergent residue. Small orange-brown spots are rust, usually from a damp weapon, a metal buckle or hook, or old hardware packed against the cloth. Fencing makers label whites do not bleach because bleach damages the fabric and the elastic, and on rust it actually sets the stain.
For mildew, brush the spots off outdoors, then soak the piece for 15 to 30 minutes in lukewarm water with a little dish soap and a splash of white vinegar. Work the spots gently with a soft brush, wash cold on a gentle cycle and air dry completely. Expect the marks to fade rather than vanish, because mildew feeds on and weakens the fibers it grows on. If a plastron still smells musty after washing, or the spots cover the armpit and sleeve, replace it: that layer is what stops a broken blade there. Chest protector straps are sold as spares, and the plastic cups just wash with soap.
Yellowing builds up wash after wash, so treat the residue. Soak the whites in cold water with a cup or two of white vinegar for about 30 minutes, rub a little of your normal detergent into the yellow areas, then wash cold with an extra rinse. Avoid detergents sold as whitening or brightening, which fencing makers warn are bleach by another name, and do not make oxygen stain removers a habit, since repeated use weakens the cloth. Washing after every session, before sweat sets, prevents most of it.
For rust, dab lemon juice on the spot, sprinkle salt over it, leave it for an hour or so, then rinse thoroughly and wash as usual; repeat once or twice for older marks. Then remove the cause: wipe and dry weapons before packing, keep whites in their own laundry bag inside the fencing bag, and replace any rusty buckle. Prevention for all three stains is the same habit: unpack after every session, hang everything to dry, and leave the bag open.