Plan A: Make a paste out of baking soda and water or diluted distilled vinegar. Let it dry on the board overnight. Then scrub it all off the next day. Repeat as necessary. If you are satisfied with the result, re-oil the board.
If there is no improvement...
Plan B - Sand your board with medium grit and then fine grit sandpaper using a sanding block. Re-oil your board.
Hopefully you won't have to resort to sanding, but I would be very confident that it would remove the smell you speak of. The smell usually comes from food particles getting lodged into dents and cut-marks made from your knife, and that allows the liquid component of your food to get through the barrier created from oiling your board.
Just a few more suggestions before you take a grinder to your board. I've actually used full-strength vinegar straight on the board (no baking soda) to remove the smell of fish and it worked. Lemon is a weaker acid in comparison. I left the vinegar on for a while (don't remember how long) then poured boiling water over it (that was more to sanitize the board than to remove the smell). Also if you live in a sunny place, maybe leave it out in the sun ?
Leaving the board out in the bright sun may help too - UV light will cut down the numbers of pesky odor-producing bacteria.
Thanks Jan and Aisha! I'll give your suggestions a try!
How long did you leave the lemon/salt mixture? I get onion smell on my hinoki boards often, so every once in a while I sand them lightly (take the second to finest grit sanding paper, and it will not damage the board), rub with salt/lemon mixture GENEROUSLY, wrap in plastic and leave for a couple of days. Then scrub, rinse and re-oil and they are like new.
Thanks! How much oil do you use when you re-oil the board? Is coconut oil okay to use?
I would not use edible oils because they can go rancid. Places like Williams Sonoma, Bed Bath and Beyond, Sears or Amazon sell food-grade mineral oils for maintaining wooden cutting boards and utensils. The amount might depend on the particular oil, but in general you apply it as long as the board is absorbing it. And it is not much.
Orrr maybe just buy a new board -.-
Don't know how deeply embedded the cheese may be in the board.
But when you have sunny and dry weather where you are, put it outside for two or three days in a row and see if that helps. Sunlight can act as a sort of bleach or purifier.
If that doesn't work, make the next board you use for cheese of some less permeable material (slate, glass, some plastics).
Oops. On rereading the thread, saw you already had sunlight idea Hope the alternate materials suggestion is some use.
Thanks for the on-going suggestions. I've tried all of these methods and found Jan's to be the most successful. Her suggestion was to sand my board and then re-oil. Thanks, Jan! Since then, I've been cleaning my board with vinegar + salt, and then re-oiling it as per Aisha and QueenSashy's suggestions, and have found that this prevents any new scents from settling into the board.