Not in DARE?

[Wilson Gray]

cat butter/catbutter : "sleep," in the sense of "brush/rub the _sleep_
(or any other similar excrescence found in the corners of the eyes or
caked onto the eyelashes) from one's eyes"

This is - or, at least, was; I haven't actually lived in Texas since
the middle '50's - the only term used or known by black East Texans for
this material/phenomenon. In fact, I myself considered "brush the sleep
from one's eyes" et sim. to be strictly poetic usages, until about ten
years ago, when I was in my late '50's. One day, I simply flashed on
the fact that what I knew as "cat butter/catbutter" (I've never seen
this term in written form) was what other people _literally_ termed
"sleep."

FWIW, there's a somewhat similar term, "augenbutter," found in German.

-Wilson Gray