Danish oil is great for this. It is half polyurethane and half oil. You can get it in clear or tinted. Takes about 72 hours before you can use it. Until it soak

Danish oil is great for this. It is half polyurethane and half oil. You can get it in clear or tinted. Takes about 72 hours before you can use it. Until it soaks in, the piece is tacky. If you aren’t looking for something do heavy duty, plain mineral oil from the laxative aisle at Walmart is $2 a bottle. If you want to make that more heavy duty, mix it 50/50 with beeswax and heat until wax dissolves. Then let cool and you’ll have what looks like candle paraffin. Work that into the wood and you’ll have it sealed. You will need to reapply it every so often (probably once a year but depends on use). Not a permanent seal but no harsh chemicals used and you get to keep caring for your special piece of furniture which some people find satisfying.