Hey Andy,
Be careful while sorting your Mum's pile and looking at base plugs, if you mess up, a base plug could be difficult for you Mum to swallow.
When I was single, I did not always have clean dishes, but I always had clean beakers in the dark room, and one night while doing a batch of photos, I used a beaker (in the US a beaker is a graduated measuring glass) to drink my beverage, I somehow managed to get the beakers mixed up, and my beaverage went into the processor, luckly, I had the first photo out of the processor, so I realized my mistake before I took a big dring of the beaker full of photo bleach.
Gus