This idea is from my Mummikins. Recently she's had the underwiring go on a favourite bra which was in good condition otherwise. As she said she was loathed to throw it away so went through her other ones and hooked out one which had definitely seen better days. She removed the wires from this other bra and then rewired the damaged one with them. Her tip is to start from the middle and work out....I hope you understand this as I am a flat chested dame and do not have the need for any additional support for my chesticicles!