Thrift Store Find: Doctor Who 1987 Mug

I found a Doctor Who mug from 1987 at a local thrift store yesterday afternoon. One side has the classic logo while the other side has a "ghost" TARDIS. Originally, this was offered as a thank you gift to those who donated to their local PBS stations.

The TARDIS is supposed to be blue and disappear when you add any hot beverage. I'm thinking the previous owner either used it too much or washed it in the dishwasher.

I only paid a quarter for it and I wanted it for the classic Doctor Who logo.