Canadian Tire has one called Salt remover.. lol. it's been on the shelf about a year now. follow instructions. might need repeat application.
I think I've had 14 bmw's in 4 years.
2 IX's -sold and parts
2 325i 4 dr - sold
4 318is all white - sold and parts
1 87 325is red - parts
1 89 325i vert grey - parts
1 90 325is white - keepin
1 87 325i vert -red - keepin
latest addition 1 88-325is red - parts
latest addition 1 89-325i vert - white -fixin/sold
latest addition 1 92-318i vert - blue - parts
latest addition 1 87 325is blk - parts.
latest addition as of 2013-Gold 87-325is auto! it's a keeper!
I personally have a carpet extractor wich works really good, but of course not everyone has one because they are expensive, i suggest spraying a good app let it side, scrub with a stiff brush and such it up