I've taught silk-screen successfully for several years.
I gave up the profilm because of it's toxic qualities and no ventilation.
I have used the Mask Ease from Sax and Dick Blick. I've also used torn
A cheaper way than the Mask Ease is to buy Contac paper. It's cheaper
and works well if you aren't doing a long run.
Kids were delighted and produced some great stuff. All speedball water
base inks can be diluted for excellent transparencies with Base.
If the stickum didn't come off the screens I used Simple Green, or Whisk.