Even a lot newer vans can suffer black mould growing on silicone sealant joints on the bodywork. I thought I was going to have to scrape out the old sealant and then re seal it – quite a long laborious job. Someone on one of the forums I read suggested the HG Mould Spray which I thought I would try. I sprayed it into a separate container and then used a toothbrush to apply it and scrub it into the joints. Very pleased I did and with amazing results – highly recommended.
Important – make sure you put the toothbrush back in the same place in its holder or else she will find out!