How to apply oil when seasoning wood cutting board?

No need for elaborate application techniques (brushes, spray, etc.).

When I worked in an old style restaurant, the Chef had me:

• clean the block with a wire brush**, then wipe free of dust
• pour any cheap vegetable based oil directly on the block
• use one of the towels from the linen service and vigorously rub the oil in
• @wumpus idea for a next day second coat is good, we didn't do that

At home, you could use a painters wire brush, or if you are really motivated: wire brush wheel on an electric drill. Or a stainless steel pot scrubbing brush. The one I used in the restaurant was similar to this:

The same brush was also used to clean the grill grate.

You can use any rag you want for the oil application. Strong paper towels would even work.

I thought applying the oil with a towel would absorb too much of the oil making it wasteful.

For a home block, I'd guess you'd have 1 tbps absorbed by the block (that's a good thing). You'd probably loose 1 tbsp in the towel--the cost of doing it right.

Also, after applying the oil to the cutting board and waiting a day or two, is it a good idea to clean it again with soap and water?

We just used very hot water on a towel to clean. Soap was forbidden. If it was soiled and permeated by something nasty, we would do the entire wire brush cycle again.

** Cleaning with the block with brush: I did it with a dry block. Some of the others would oil the block first, then liberally salt for the abrasive property, then wire brush it. My way gave similar results, but was easier.

I wouldn't use coconut oil due to its solidity which explains why it's still sticky, although you can rub it in more; this is a list of good choices. In particular, mineral oil is good and easily obtainable. I also find paper towels to frequently leave parts behind.

Make sure your cutting board is clean (no dust) and dry. Brush the oil on a section of your board and rub it in with a lint free padded cloth, rubbing with the grain. Continue until the board is done. Let sit overnight and then rub off the excess with a lint free padded cloth.

Also see here and here, for example.

This is what I do with my chopping boards:

1. Wash with warm soapy water, scrub with a nylon cleaning brush.
2. Dry with paper towels and wrap in fresh paper towels for an hour.
3. Remove paper towels and let dry for 24 hours in shade, do not expose to sunlight, put on a radiator or use other sources of heat to dry more quickly.
4. When dry, sand the board all over by hand with a 160 grit sandpaper.
5. Apply food grade mineral oil with cloth. Be generous.
6. Let the wood soak mineral oil for 12 hours and remove excess.
7. Apply mineral oil two more times with 12 hour waiting period and let it soak 24 hours after the last application.
8. Remove excess oil and sand by hand with 400 grit paper.
9. Use natural cosmetic grade beeswax blocks and rub them on all surfaces of the board to trap the oil inside.
10. Use a hairdrier on low/medium heat setting to melt all the beeswax and it will go into all the wood pores.
11. While melting the beeswax, rub with cloth to remove excess wax.
12. Board is ready for use.
13. Use only warm water and mild detergent to clean boards after use.

I am quite happy with this way of doing it and your board is likely to be extremely resilient to cutting and chopping although it depends on the wood quality and cut as well. I do not need to "reseason" boards for years despite constant use.

First, make sure to get the right oil.

You should only use food-grade or medicinal (non-odorized) mineral oil.

Never use vegetable oils for cutting boards, that will eventually go rancid. The odor will be bad for the kitchen, but it can also impart itself onto the food.

Make sure the board or block is dry, or else the water will lift the oil, and prevent it from soaking in. You can use any clean rag or paper towel and rub it on. For regular maintenance, a very thin coat is needed. For first time use, if not already seasoned, add the oil more liberally, and do so several times over a couple of days to let the oil soak in.