Went to view oriental wool rug today. The problem is that there are brown spots all over it and upon blotting with just cold water, they seem to transfer but tips of fibre look to have been dyed brown due to what ever this is. The rug has been for the last few years been kept in a plastic bag in a loft. The customer has assured me that the brown spots were not there when it was placed in loft. I was thinking it may have been caused by not being able to breath and I have a feeling it may be the lanolin oil from the wool. I have come acros this problem before in a basement property and the brown spots seem to have spread where ever it was natural fibres. So could this be the oil from the wool or some kind of spore?