Mylar for free

I use to use the back side of Cystal-Craze background material for
reflective material, using left over stripes from backgrounds.  Then one day
while finishing off a bag of Lays potato chips, I noticed the shinny inside
of the bag!  WHy not?  I cut the bag and cleaned the silver side with "Simpe
Green" and washed off with water.  I'm sure there are better mylars but you
can't beat the price.  I don't expose the stuff to water as I have glass
tops.  It won't last for ever but either does a bag of potato chips.