Another good way is to take the time to separate the parts into lots by make and offer the lots for sale to collectors or dealers with interest in the particular makes. There is of course no way to get anywhere near retail value for the inventory other than devoting years to slowly selling them off via HMN ads, ebay, or swap meets, as I do with my large Studebaker inventory. I know that the day will come, just as for your dad, that my retailing days will end & what remains of my inventory will be sold off cheaply in large lots or by auction.