Once in a while I have to pay some attention to my "nystpinnar", needles for nalbinding and the hooks for Shepherd´s knitting.
I most often use olive oil for this. I coat them with the oil, I wait for a couple of hours and them I rub the oil off and let them "dry" for a day before storing them away again. All my "tools" made from wood are not treated with any kind of protective coating other than olive oil. I would not advise to do this if your tools are varnished or coated with anything else, since the oil might start a reaction that you do not desire.