Basically, there are two major types of polyurethane (oil-based and water-based) that are good for clear coating. The oil based will give you a thick smooth result but may warm up the hue by adding some amber tint over some time. So the best choice then will be using the water-based version as it is easy to apply and it reveals the peculiarities of the wood. You may suggest using a spray version as you can see in the attached file. Please, keep in mind that sometimes the wood might have some spots of natural resin or oil. In this case they should be sanded off so the color won't turn into yellow or pink in these spots.
What is the best option for a Natural Look stain?
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