Sew Clean Tip

I got a call this morning from Sue, she's a quilter out there in Quiltland who says she loves Sew Clean.  She had a small problem.  She used it on an older quilt that had muslin in it, I'm thinking it was the background.  She said she uses Sew Clean all the time and has never had a problem with it.
However, on this "older" muslin, the Sew Clean left an outline of the spot where it was sprayed on. She took spring water, dabbed it and the stain is now gone.  This happened to me as well, I thought I had gotten carried away with it and had put way to much on.  I thought, let me try to blot it out with water, however, we have well water and am not to sure of the minerals that are in our well water.  I used the bottled water and dabbed and the tan outline of the stain went away and has never come back.