Restoring an old Desk

I just bought an old Oak Scottish Schoolmaster's desk and file cabinet made in Glasgow Scotland in the mid to late 1800s by James Simpson. They are in decent shape but the wood is dry with some cracking.

I plan to use these items not restore them for sale as antiques. I put WATCO on most of the old tool handles I restore. I am wondering if it should work for this job as well? Although I do not plan to sell these items I would prefer not to ruin them in terms of their historic value. Any help is appreciated.

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Restoring an old Desk