I wanted to post a warning to prevent someone for doing what I just did.
I was wanting to clean my engine case prior to repainting it and re-assembly. I thought I would use 'The Works' toilet bowl cleaner to clean an AS41 engine case, since it was pretty good at toilets and heard that it was used to clean heads by another person. When I first poured on the cleaner, the chemical started to foam, so I let it sit for a minute or two, then I rinsed with cold water. Thinking how it cleaned pretty well, I poured some on the case again and it foamed, but this time I noticed a wisp, of what looked to be smoke, then, POOF! The case's surface had lit up with green flames! It extinguished itself as quickly as it ignited.
Here is a picture of the bottle an a close up of the ingredients:
I am not sure if the cleaner was having a reaction with the grime and water or what. I didn't notice any damage to the case, so I don't think it was reacting to the magnesium.
Just a warning...