Beware! This can damage the lenses if they have anti-reflective coating. The heaters at the optometrist’s office have guards to direct the heat away from the lens and towards the frame. Opticians are also trained to avoid manipulating the frame in ways that can unnecessarily stress (and damage) the lens.
18” dishwashers are still very easy to get ahold of. I’ve recently replaced one and while I had more limited options compared to 24”, there were still dozens to choose from.
I’ve had uni a few times and enjoyed it but I really can’t get over how it looks.