[hydrogen7800]

This takes me back, as well as some of the replies to your post. I still have most of my drafting tools from high school, including eraser shields, etc. one thing I didn't see you mention, and would help with dingy vellum, is a pouch with eraser granules you squeeze to put a thin layer of dust on your drawing. This will pick up excess graphite as you slide your t-square or parallel over the drawing.

[dougdude3339]

I used one of these bizarre pouches as a gentle final pass to clean up drawings. The graphite "smear" from the t-square happened with every drawing - thanks for sharing this top. Before starting a new drawing I would wipe down the tools to start fresh!

[hydrogen7800]

When I learned, we were told to keep that dust on the drawing the whole time rather than just the end. We always had a small dusting brush nearby to sweep it off as it got dirty.