shrinky dink - toaster oven advice!

[vidaliasparkle.livejournal.com]

hey everyone! 
I adore making the shrinks but I have this little problem. I use part of a paper bag to bake my shrinkies in the toaster oven and I have a lot of trouble with the paper burning!  Do you use paper bag or something else to bake them on? do you put it directly on the wire rack, or on one of the metal trays? other possible suggestions? 
thank you!!!