Don't wipe your mouth on your sleeve - use a napkin.
Tips
usage
揩 is more colloquial and physical than 擦 (cā), both meaning 'to wipe'. 揩油 (kāiyóu) is an idiom meaning 'to take advantage of someone' - literally 'to wipe off the oil'.
扌 is the left-side form of 手 (hand). Wiping is something hands do - 揩 sits in the manual-action family with 擦 (rub), 抹 (smear), 拭 (wipe), 擢 (pluck). The hand radical immediately flags this as a verb of physical contact.
皆 (jiē) supplies the sound, drifted to kāi. No semantic contribution - the meaning sits entirely with the hand radical. Same phonetic series: 楷 (model script), 阶 (step), 谐 (harmony) - all kāi or jiē pronunciations.
