I recently purchased the 40w S1 and prior to purchasing had read (somewhere) that I could engrave on clear acrylic if I masked it first or painted it black.  I purchased (for testing purposes) yesterday a piece of clear Glowforge acrylic with masking paper on it, and created a file to test the engraving.  Since I don't get the option of clear acrylic in the Material Selection by Machine section, I selected pearl white opaque (which might have not been the right setting to use).  The machine didn't even cut through the masking paper.  I could see the image on the paper, but it never even cut through it.   If I can get away with not returning the machine (it's only been used 3 times) and upgrading to the P2, I'd like to do that because this is all new to me and I feel like I may be missing something.  Suggestions or help?  Thanks!