* Mineral Oil - A Non-Drying Oil Finish
You can find a variety of products with mineral oil alone, or with various waxes and other additives. Sometimes they are called "salad bowl" or "cutting board" finishes. A popular combination is mineral oil and beeswax. Some people do not like mineral oil, because it comes from petroleum. They say it can add a bad taste to your food or give laxative properties. I have used pure mineral oil and mineral oil with beeswax/carnauba wax on cutting boards, and had no issues at all.
Mineral oil finishes repel water but do not dry. You apply them by letting them soak into the wood, then wipe them off thoroughly until the feel is right. Every once in a while you should reapply the finish to restore the properties of the bowl or cutting board.
Here are products that I have used on cutting boards with good success:
Pure Mineral Oil is available everywhere, including the drug store as "baby oil." I have used this:
I switched to this, and prefer it to pure mineral oil. It is mostly mineral oil, with beeswax and carnauba wax:
* Natural Drying Oils - Tung Oil, Walnut Oil, some kinds of Linseed Oil finishes (but not all!), and more.
Unlike mineral oil, a natural oil finish uses a drying oil. A drying oil "polymerizes" (hardens) to make a protective finish in the wood. Oil finishes will darken and "amber" the wood, and most people like the appearance. Here are two examples:
To be honest, oil finishes look almost the same as one another. The primary differences between them are how long it takes for them to cure (dry) and how much they darken the wood.
* Expensive, Fancy Food Safe Oil Finishes
In addition to buying natural oil finishes, you can also buy fancy, expensive, food-safe oil finishes. Some people swear by them. I have Tried and True Original and their Varnish Oil. I have also tested Odie's Oil. They are food and baby safe, and look very nice, but not much different than other oil finishes. Most are based on a polymerizing linseed oil, where they use special processing rather than toxic metallic driers. They have a wax or varnish additives. Are they better or different than other oil finishes? In my opinion, no. See this thread, where @AmishElectricCo
and I have posted photos of different oil finishes on different woods:
Here are examples of the fancy finishes I have tried. All of them are baby safe and food safe. They have great marketing hype, and I know some people who absolutely swear that they are the best. Frankly, to me they look the same as regular oil finishes (or ones you make yourself by adding your own beeswax or carnauba wax):
I also have Tried and True Varnish Oil, which is food safe, but I would not want a varnish coating that could flake off in my food, even if it is safe:
* AVOID: Boiled Linseed Oil (BLO) and other oil finishes with metallic drier additives.
Boiled Linseed Oil (BLO) is a popular oil finish and it looks great. Unfortunately, the "boiled" part is misleading. In this case, it means that they added metallic driers - great for furniture, not good for a salad bowl. (The polymerizing linseed oil that they use in the fancy, expensive oil finishes does not have metallic driers, which is why they are food safe.)
* AVOID: "Danish Oil" and "Teak Oil" finishes.
Even if they are called the same name, they are not all the same. They are blends of different products. They may include undesirable additives, and many of them are not food safe.
* Not all oils are drying oils. Oils used for cooking are sometimes used as finishes, but Not all of them are drying oils. Other "kitchen oils" can go rancid and are not recommended.