Divokittysmom, actually the ones that break are light in color. Go figure!
As for Sewer's Aid, that might explain a nasty little surprise I had a couple of weeks ago. While happily stitching away a black blob of something fell out of the machine onto the fabric. I tried to blow it off, but it wouldn't budge, so I stopped the machine and used my finger to remove it, but it smeared! Arghhh! Happily what I was working on wasn't a big project, just a needle case on muslin.