Onion smell getting on fruits I use a recently-purchased bamboo large-and-heavy cutting board to cut/chop/dice/slice veggies and fruit.  However, my routine is such that I typically dice a red onion at night, and a green apple for breakfast.

I've noticed that the red onion smell and, to some extent, taste gets on my green apple in the morning. 

I read online about people treating their cutting board with coconut oil or something before using it. I failed to do that.  Is it too late to do it now?  Will it solve my problem?  Are there other ways to prevent the onion smell-and-taste to get on fruit?
My experience is that washing doesn't effectively get rid of onion or garlic odors from cutting boards. 

Either get another - maybe lighter weight and cheaper - cutting board for fruits, or flip your current board over, and use the "bottom" side for delicately scented items, etc. Mark the "top" side with an "o" for "onion" (or some such discreet indicator) in permanent marker, so you will remember in future which is which.

Getting housemates to comply is a separate problem.