Inspiring Quilters, Stitch by Stitch
Be careful how you handle & clean your plastic rotary cutting rulers. The grids and markings (on the bottom surface) can be damaged or removed if cleaned with the wrong solvents or liquids.
A friend just tried cleaning rulers with rubbing alcohol, and found that this removed the grid lines from 1 brand of ruler but did not damage a different brand of ruler. (So this can vary between different brands of rulers.)
I recently read that fingernail polish (which may contain acetone) should not be used to clean some rulers.
I have not tried to clean my rulers, but I expect that a gentle wash with cool water and dishwashing soap might be safe, provided that it did not leave residue or streaks on the ruler. Avoid exposing the ruler to heat, which might soften or deform the plastic.
Similarly, the grids and markings could be damaged by rubbing with a rough, abrasive material. Be careful when using sandpaper around your rotary cutting rulers! I would be cautious about using them to cut rough fabrics, perhaps including burlap.
Our plastic rotary cutting rulers are an investment for quilters -- handle them with care!