Ultimately, we can't tell you exactly how long you can leave butter out. We have no problem with leaving butter out to soften as long as it is well-covered. It usually doesn't take us more than a couple days to go through a stick anyway! We've never had rancid butter in that time.
For complete instructions, see my weekly column. Note: The vinyl melts in just a few minutes and is warm to the touch when you pull it from the 200-degree oven (don't use a hotter oven or the vinyl will start releasing toxins). You can form it by hand immediately, but use leather gloves if you're nervous. All beginners in Record Upcycling should try a bowl.
Can be used conâ¦stantly at about 80 degrees, and withstands 95 degrees Celsius for a short time.   High-density polyethylene (HDPE), used for supermarket plastic bags, motor oil and laundry detergent bottles, melts at a slightly higher temperature, 130-137 degrees Celsius.