Colorfast to ... silicone?

Today we learned that an outfit of mine (which had been languishing in the club bag for a while) is not colorfast to *something*, and we think that something is liquid silicone. We know this because there is muddy purple-black all over the nice light blue striped cotton sheets (and some got all over the me).

We'll see how OxiClean works; we don't have Soilove at this point in time. (A shower worked pretty well for me.)