In my kitchen, the workhorse of any meal prep is a huge, heavy, 15-pound butcher block that I bought nearly 15 years ago. Minor scratches and stains aside, it still looks as new as the day I hauled it home.
I don't baby it; I use it nearly every day; and I've taken every kind of sharp object to it, from a bread knife to a cleaver. Unlike the countless flexi mats and plastic boards I've used over the years, wooden cutting boards are very low-maintenance for how long-lasting they are. Post-prep clean-up merely entails a wipe-down with a rag, or for messier jobs, a little soapy water. Twice a month I do a deep clean, and despite the name, it takes only five minutes of my time using two things I already stock in my pantry: citrus and salt.
As previously mentioned in this article, citrus is a powerful natural cleanser in the kitchen. It removes stains, disinfects, and deodorizes, and you don't even have to sacrifice a new lemon (or orange or grapefruit) to the task. A just-squeezed lemon works just as well as one that's been sitting sadly in the fridge for a few days. Salt has a mild abrasive quality that scrubs the surface of the wood without damaging it. I like using a coarse salt such as kosher to really get in there and scrub away food stains and remnants, but table salt is fine if you deep clean more frequently, or your cutting board is fairly clean to begin with.
Depending on how frequently you use your cutting board, you may need to deep clean it once a week... or even just once a month.
To begin, sprinkle a bit of salt on the surface and rub it in with the cut side of a lemon. On areas with discoloration (from berry juice, for example), I'll squeeze some lemon juice onto the stain and let it sit for a few minutes while I work on the other areas. (I always feel a little glee when I see the cleaning "solution" turn slightly gray and grimy!)
Scrub all over the surface and then rinse with warm water. Do this on both sides of your cutting board, including the edges. Never wash just one side because it could cause warping over time; along the same lines, never use your wooden cutting board as a drying rack as the constant moisture could cause dullness and splitting.
Thoroughly dry your cutting board with a towel. Lean it against the sink or prop it upright to air dry for a few hours (or overnight). Once it's completely dry, you can use it like normal. With consistent deep cleaning and care, your cutting board may last another 15 years!
For more tips on using citrus as a natural and non-toxic cleanser, check out 3 Ways to Clean With Citrus In the Kitchen.