Aleš Lombergar

provided that you’ve used a vitreous paint for that purpose, there are some recommendations I’ve seen or used:

if the glass is a container with a handle, use a “paper clip” hook and suspend it from the bottom of the oven rack that’s in the top level/position

if the glass is a container, fashion a cone of aluminum foil and invert the glass over the cone

you might also try crumbling foil into “logs” or cylinders and place 3 -4 of them equally spaced under the object [yes use a cookie sheet under the foil logs so you have a level surface,

You are feeling rather creative tonight aren’t you??? Wish I had some of your energy….There are a couple of things you can use, it seems to me the temp is quite low on this project so you could use newspaper (under 450 degrees) on a tin tray. Just let it cool in the oven. You can use a telflon sheet, the best by far, if you have one. Failing that I have used parchment paper. All of them work, just be careful to let things cool down without tipping, ove glove works for that.