At the same time, I put the lid of our telephone junction box (connection box)  in the dishwasher, which removed most of the paint applied over the last fifty years! I will leave that in for another wash.
 BT35A clearly marked GPO, so been there for a while. Incoming cable has 7 wires, but only two are connected. A few more inches of cable connect the BT35A to the master socket. Most odd.
 The dishwasher and washing machine are also excellent for cleaning grubby Lego. Does not do the sticky labels many favours though :-)