I think I once told you that you could use olive oil for the inside of the woodie but I wouldn't go that route for the whole mod.Personally I wouldn't use butchers block either.i'm pretty sure that at some point in their evolution woodvils were finished with tung oil maybe @Spydro or @Papa_Lazarou can help out here.i would suggest you take a look at Danish oil,there's lots or ways to use/apply it and it's less pt than tung oil.i can give you a link to an sa manufacturer if that's the way you would like to go
I know Reosmods used mineral oil on the inside of the Woodvil's, probably teak or tung oil on the outside. I use Howard's Sun Shield on all of mine both inside and outside. With over the counter wood finishes, wood species plays a roll in which ones work the best on a given species. Some woods and not oily, some are very oily and the wrong finishes may never dry to a hard coat on them. Information on-line from a search can be your guide about wood species and the wood finishes to use on them. But if your Woodie is not damaged and just needs a sprucing up, liquid wax finishes like the one I use, Renaissance wax that many folks also use are all you need to preserve/protect it. I have a set of artists brushes I use to get ii in every nook and cranny, let it soak in for a time then remove the excess and give it a quick buff with a soft cloth.
All woods are toxic to some degree, some species and the higher grades of many more species can be very toxic. And they get treated with even more toxic wood preservatives by jobbers, distributors, etc that are the "middle men" before the woods get to the retail market. I crafted custom wood animal calls for over 50 years from most of the species of woods worldwide that had high grade figure, color, etc. So I bought most of my woods direct from sawyers in the places where they grew and imported them to the US. All the later years I made my own finishes from scratch using 100% pure ingredients, gave them 20 coats because I was only using high exhibition grade woods then that would by default be more toxic. Important to me because they would go in mouths, be slobbered on, chewed on, etc.