When do we use "golchi"?
Golchi=other things eg. "golchi'r car"=Wash the car.
Ymolchi=for yourself/a person washing themselves "Mae hi wedi ymolchi ei hun"=she has washed herself. Ymolchi is often said as molchi
This sentence sounds really odd. The perfect tense when talking about a period that's firmly in the past?
"Yesterday, I washed" or "I have washed today (already)" make sense.