It is not usually considered worth restoring most girders when bent or very rusty. They can easily be cut down to form the shorter girders which are less common. However, when an expensive 18.5" or 24.5" girder is damaged, it would seem worth trying a bit harder.
1. Here is a rusty bent 24.5" girder: The white wire indicates the bend; the upper web has become permanently stretched.
6. The solder is then filed flat, and the whole girder treated for rust (see separate article Meccano restoration: stripping rust). These are some of the parts treated by this method.