When Blue was small and the teething started, I followed the excellent advice on this forum and gave him a large frozen carrot to gnaw on. He had a nibble on it, then carefully buried it in the garden! Obviously, he imagined it would still be frozen when he went back for it.
The next day, he went and dug it up, and moved it to a new spot elsewhere in the garden.
On the third day, he dug up the slushy mess that remained and carefully re-bured it in another 'secret' hiding place, known only to him (and me!) Bless him
He still buries his treasures, balls, bones etc. It's amazing how they have that instinct, isn't it?