This isn't really true. The heating elements are pretty much entirely a resistive load, which do not cause arcing when switched off. What desoldered your PCB might be the heat itself.
There was visible arcing every time the toaster popped up the toasts though. Now that you mention it, I'm kinda curious what exactly was causing it. (Too late of course.) It's not the first toaster I've seen that produced a flash of light every time it was done though.
This isn't really true. The heating elements are pretty much entirely a resistive load, which do not cause arcing when switched off. What desoldered your PCB might be the heat itself.