Rust!

[Bristim]

Doing a bit of cleaning recently and found that under the soundproofing in the boot are two 'rubber bungs' which fill two large holes in the boot floor. Around both was quite a bit of rust and since the metal is only single thickness, this has been eroded.

I cleaned it up and stuck a load of Hammerite over the affected bits for the moment, but want to stop this going any further.

Anyone else encountered this and any ideas what might be causing the rust - do the bungs hold water against the metal?

[bothwell_buyer]

I have the same with the bungs in the front footwells. Ye - they do tend to trap moisture between the rubber and the metal as there isn't a good water seal. I put red oxide on mine, but have stripped out the car with the intention of treating the rust first then painting.