Get yourself a wet/dry vacuum or even a steam cleaner for your floor mats and carpet. It may sound like a pain, but it's best to remove the seats for a good job. Thoroughly clean the carpets with a good fabric carpet cleaner with disinfecting properties (yes we are making one currently). Then vacuum it all out. Clean the hood-liner with our Vinyl Care and glass with the Naked Glass cleaner too. Once finished, leave the car with all doors open to totally aerate.
A lot of the musky smell you get from cars is from mould in the carpet. If the vacuum doesn't remove it, we've found that rather than using “masking” agents to hide the smell short term, it's best to just replace the mats, then if the smell is still there, replace the carpet and more importantly the felt underneath with brand new ones. Be sure to clean the steel floor too; any mould in the car needs to be removed as it can quickly grow back.
For all the other surfaces, especially where the mould is visible, use our interior products. Following the instructions on the bottle, spray the product into a microfibre applicator pad, wipe off the mould quick and easy. Be sure to swap this applicator for a fresh, new one often, as the mould spore build-up in the cloth can help spread the infestation further!