Just handwash it in hot sudsy water immediately after use. Use only a plastic scouring pad if pastry residue is difficult to wash off. Rinse well and dry it completely with a towel. Store it in a drawer or cupboard.
It generally is not necessary to condition wooden rolling pins as careful washing and drying is usually sufficient. My wooden pins are decades old and are still in excellent condition.
If however, your pin has had too much heat and there is fear of the wood cracking from excessive drying, you could use a salad bowl oil or mineral oil rub to condition it. Ensure that the oil you use is safe for wooden food bowls or bread boards.
Dishwasher use is not recommended as the heating cycle can dry out the wood and a long wash cycle would overly soak the pin.
Read More About Baking Tools: