gukuyēngeza (-kuyēngeje)     v    1. to polish, 2. to smooth out
polish    (to) gukurūngira, gukuyēngeza, gusēna
En-En dictionary 
smooth    (to be) kurēmba
(to ~ out) gukana, gukuyēngeza
(to make) gukurūngira, gusena, gupfunyūra
En-En dictionary