Big no no for grease.
A long lasting 1 way bearing need attention and maintenance.
You can use after run oil and lint free clothes to clean the roller bearings inside the 1 way unit.
You can put 1 drop of after run oil ( or 1 way bearing oil to be specific ) as the final touch before putting all back to the main shaft.
Do not put too much oil. Wet one way will attract more dirts and shorten its life, and slip problem too.
On Road : Xray NT1 , RX8 , T4 || Mugen Seiki MRX4-R , MTX4 , MTX3 prospec || Tamiya M03 , M04 || Top Racing Sabre FD2
Off Road : Xray XT8 || Hobao Hyper 8
Radio : Futaba 3PKS || KO propo EX-10 eurus