If you can remove the carpet then even better . Put the carpet outside in the sunlight , the sun kills off the mildew. Then add lemon juice to this part of the carpet , again leaving the the juice to dry in. Once the lemon juice has dried, wash with a sponge and warm water , This should rid the scrub the carpet over again with a excellent carpet cleaner or steamer and place the windows open and let it dry the air isn't getting to it so that's how your getting the shape, or solely replace the carpet if it keeps coming back then the pours of the shape are still there and this wont be extremely excellent for you if your breathing them in .my sister has solely given me a small tip for you ,as your caravan is not in use place a muesli bowl in each opportunity , (IE) bedrooms , kitchen vicinity and on the living opportunity part . and fill the bowl with salt all the stale air get absorbed into the salt consequently no more shape , she swears by it and has had a caravan for over 10 yrs she by no means had a conundrum .
Thanks
Upholstery cleaning