Every once in a while, he'd sell off some Tamiya or Fujimi kit he bought, for a discounted price, but the kit would always be missing the tires. The rest of the kit was there and unbuilt, but not the tires. I once confronted him about that, accusing him of building a diorama of a tire store, of maybe racetrack's tire wall, and he sarcastically replied that I found his 'secret'.
And, no, he didn't build any models with the tires...