Green’s Dictionary of Slang

process v.

[the straightening process]

(US black) to straighten one’s hair.

[US]R. Abrahams Deep Down In The Jungle 96: He was short and very much the ‘dandy,’ and had learned to do ‘processing.’.
[US](con. 1950s) D. Goines Whoreson 67: I grabbed a handful of processed hair with my left hand.
[US]C. White Life and Times of Little Richard 64: His hair was processed a foot high over his head.
[US](con. 1964–8) J. Ellroy Cold Six Thousand 376: They wore pendants. They wore processed hair. They carried mock-gold guns.

In compounds

processed mind (n.) [fig. use]

(US black) a black person who appears to prefer to see things from a white perspective.

[US]D. Claerbaut Black Jargon in White America 76: processed mind n. a mentality which is alienated from black culture and tends to take on white attitudes: He may have a natural, but he’s still got a processed mind.