If your cutting board doesnt look like the photo above, its time.
Using your fingertips, sprinkle a few drops of water over your board.
If the board has been properly and freshly seasoned, water will bead up on its surface.
This is a good indication that nothing is going to penetrate it.
Thats a sign that youre ready for another layer of oil.
Im pretty sure my cutting board is like a sponge right now, so off to oil I go.
Check out Kenjis post below for more instructions on seasoning and maintaining your wood cutting board.
How to Season and Maintain a Wooden Cutting Board| Serious Eats