I just purchased an Otter Ankermesser #174 with sapele wood handle. Should I put something on the wood before using? Otter provides Ballistol with the knife. Ballistol claims it can be used on wood yet when I inquired with Otter they told me to use ballistol only on the blade.

I've used Ballistol on gun stocks without any issues. It will darken the wood slightly, some more than others. Since sapele is a hardwood much like mahogany, I'm not sure what it would hurt, but if the factory says no, then I would assume they have a reason. Odd that they would provide Ballistol for just the blade though.

Anyone have any experience with linseed oil?

It depends if the wood is stabilized. If not it will still be porous. I like Tung oil, or even paste wax and buff. How bout some pictures!

If the wood isn't finished already, some pure tung oil would make a fine finish. Instructions for a tung oil finish are all over the web.

Linseed is similar.

Birchwood Casey's Tru-Oil is mostly linseed oil, with additives, and does a very nice job, and is a little easier to handle than pure linseed or tung oil.

Real tung is good. I've also used walnut oil with good success; that's a good one because it can be found at nicer grocery stores.

Tung oil would be great here. I would opt for it over linseed oil, unless you're talking Birchwood Casey Tru-oil, another very good choice.

In any case I would seal the wood first if it's otherwise untreated. Minwax makes a good "Sanding Sealer" for use on bare and unstained wood. I've gotten some excellent results with it.

If you use linseed oil ,please be careful with the rag/cloth if you use it to apply. Once use they can cause a fire.