I have started cutting my partially used proofgrade materials into 10" X 12" pieces and centering them on the crumb tray. This allows me to cut to the very edge of the stock. With this method you can cut small objects out of even severely used pieces.
This seems like an obvious tip but I searched the community board and did not see it. If it exists elsewhere please delete this post.
I think there are some posts sort of like this. I use a GF ruler as a side spacer to get the material in a place where I can get to the edge. Same for the bottom. @Jules posted a series of designs for them of different sizes but she called them something other than âspacerâ.
Mine are so full of holes I can usually just snap them in two to get to the unused outside bits.
Dang â I canât find that post either. Thought it was some variant of âparallel setsâŚâ
If you have a pro, use the slot to cut from the end first, similar effect.
Alternately join the dark side and start using non-PG materials that are much less expensive 
It was these guys - but I didnât share a file for themâŚtheyâre just rectangles cut to the width shown. (Tardis optional.)
Thatâs okay, doesnât hurt to see it again, especially for newer folks!
Ah yes, spacer sticks. How could we forget? 
I usually cut the sheets on a sliding mitre in strategic lengths to allow edge to edge usage. The 2 pieces pictured are a full sheet.
