How much money do you have? Can you buy a second hand one to use? Rareness aside, if you want to keep them pristine, don't use them. Do you have similar knives that you can use? Are those two filling a niche in your user line-up, that is void of a user?
I own one wakizashi, it's from Swamp Rat. They don't make them anymore, but they were made to be used. So, I use it. At any time I could have it stripped, convexed, and polished. That alone would add to the value, at least to somebody, and I still would have got to use it.
Besides, time will tell how rare or collectable something is, and there will always be better knives, better steel, and more collectables.
I have a few knives that I don't use. Most are older inherited knives, I don't want to damage or loose those. A few others were limited runs and I bought two of them, one is a user the other will be someday.