Despite cleaning the car, all the wet weather has produced a verdant green "moss" on the door window seals.

I clean it off using an old tooth brush and rinse but it loves the old fashioned canvas seal material and grows back

vigorously. Any tips on how to kill it without spoiling the paintwork?

Excellent question. 

I seem to recall Honest John recommending a product called 'Wet and Forget' in reply to a similar question from a reader.

I've not tried it myself as it's quite expensive and I've already got stock of a similar product for treating my drive. Maybe when that is all used up I'll get some.

Like yourself, I usually use a small brush but it always comes back.

 

The wet and forget product comes in various guises.  It's also known as spray and leave and can be either concentrated or used straight from the bottle.  I've used it on my garden fence and it does work.  It kills the green mould and turns it into a silver grey colour.  Never used it on the car though.

I was just wondering about Milton "mild bleach" but its reaction with the paintwork is an unknown.

Soda crystals will kill moss no bother. I'm not sure about car paintwork and soda crystals but cleaned my, presumably, powder coated mouldy Weber BBQ the other day no trouble at all plus I use them for cleaning moss off patios/flags. On the packet, it only warned about contact with aluminium.

 

I did a quick search for problems of soda crystals and paintwork and didn't find anything good or bad but have a look yourself.

 

I think soda will be too strong. It's what I use to soak both my BBQ grill and oven shelves to get them spotlessly clean!

You can make weak, medium or strong solutions with it.

 

White vinegar may also work.

 

I guess care needs to be taken to protect the paintwork and not destroy the rubber, too.

 

After my last post I applied some white wine vinegar I wiped and rinsed the body paint.

It rained for a couple of hours after but the seals look fine now.

Thank you all.