Q: I own a four-year-old MX5 that appears to have moss growing on its hood. It's very resistant to soap and scrubbing, so what should I use to remove this problem?
A: Over time, most convertibles will need their hoods rejuvenated. The waterproof coating on the hood gradually wears off, allowing moisture to penetrate the material and things to grow on the surface. On cars with unlined hoods, mould or fungus can actually grow on the inside due to water seeping through.
There are several products available to clean and reseal your convertible's roof. Autoglym's Cabriolet Hood Cleaner comes with an abrasive pad to help remove stubborn stains, but similar rejuvenating products are available from Renovo and RaggTopp. These are all available from high street shops or online.