With parchment paper, the main concern is temperature rather than length of time. Parchment paper is generally rated safe to around 450° F (232° C), so don’t use it if you plan to cook anything at a temperature higher than that.
It depends on how strong your lungs are. Some people can hold their breath for a while, while others have weaker lungs. Don't try to hold your breath for longer...
You can purchase a light table for art, such as an Artograph LightPad 920. You'll have to be somewhere dark, like a dark room or anywhere with the lights off,...
Try toothpaste, which works really well for soot and scorch marks. Put a thin coat of toothpaste across the scorch, leave for 10 - 20 minutes, then clean off with...
