Lets back up. Borax is NOT a preservative, just a moth proofer. Im not sure how big a fee is too big for you, but heres some help. Aside from cost, lets just talk about what works first. If its summer velvet rack from this time of year, it must be frozen immediately. Theres too much blood and fluid in them to stay stable. From there I reccommend freeze drying them. Thats done in a chamber, not in a frost free freezer like some might suggest. If its a late velvet, like a September Mulie for example, now you have some options. If you wanna come back with specifics, Ill help you out. I can reccommend a freeze dryer in your area as well, Id guess. Let me know...