Cleansing it is fairly simple. There are a few options, and you can combine some or all of them. I would do a banishing directed at the wand, then follow up with purification by passing through some incense smoke (Air and Fire), cleansing it with Water by running it under some (though a running water source is better IMO) or burying in salt (Earth). Alternately, you could bury it in about 6" of dirt in the yard just before a rain storm and let it sit through the storm, letting Earth and Water do it naturally. There really are many ways. When you do it, you are going to want to see the impurities and energetic charged being ejected and/or absorbed into the elements used.
Then you fashion it to your liking or purpose; there really is no wrong way to make your wand unless a system demands specifics; personalization is key.
You then consecrate your new tool in whatever fashion works for you. If you are going to add any oils or blood you will want to put them on after the initial consecration, so the anointing bears more significance. Then charge it with energy or intent, much like the way you charge a sigil or stone, pouring energy through sight or physical transfer into your new tool until it glows.
I suggest not using chemicals or man made varnishes on it; some chemicals negate certain energies, some don’t, and who wants to guess? If you feel you need a finish coat then linseed oil works very well, plus you can always re-finish it with very little hassle. A finish coat of linseed is also a good opportunity to add oils or blood to the wand, as the wood absorbs it during the drying time.
I also suggest wrapping the wand in a bit of white or black cloth to give it a bit of protection from yourself, especially if you store it openly or near anywhere it could be exposed to energies. You would not want to do a banishing and accidentally throw off the charge on your wand, would you? Side note; this really does go for most magickal tools/objects, IMO, except most jewelry worn on the person; even then use caution.
I final dedication or declaration of intent of use adds a nice effect for some. I like to do it. It has a similar psychological effect as when you step back from a laborious task that you have completed to perfection and observing the result with satisfaction; in other words, you know that wand is going to work just as sure as a new sports car right off the assembly line.
Hope this helps, and enjoy your new wand!