I made 5 hard maple and purpleheart (wood whisperer style) chopping boards for Christmas.
After lots of research. I finished them with Liquid Paraffin BP available from a chemist
Liquid paraffin and mineral oil are the same beast and do form the basis for baby oil.
I paid about £1 for 150ml and used 1.5 bottles, I also added some pure beeswax to some warmed liquid paraffin to make a more waterproof outer finish.
You may have to persuade the pharmacist to sell you more than one bottle at a time, as it is sold as a laxative ... they may be worried that you may go OTT with the laxative ...... I couldn't quite figure out why, especially given the warning that if you take too much, a side effect is it leaking out of your $$%! ..... nice
Its a bit messy but penetrates the wood well and using the old aadage
once a day for a week
one a week for a month
once a month for life
the boards should last forever.
hope this helps Simon