The other posts about using a sharp blade are true as well a dull blade cuts a wider groove allowing the fabric to be pushed into the mat.
Cutting mat has grooves.
It reminds me of a c filter material there is a trick to removing all of the fabric particles from the cuts in the mat.
To clean the fabric whiskers from my rotary cutting mat i dry scrub it with a greenie which is really designed for scrubbing dishes.
Reset the mat borders for the desired spacing of the v groove from the mat opening.
If you have a self healing cutting mat it needs to be re hydrated to stay self healing.
When you use a rotary blade on a hard plastic cutting mat you leave a small groove in.
Soak the mat in room temp water for about and hour let dry.
A v grove provides an accent line around the outside of a mat opening giving an effect similar to the ruled lines on a french mat.
The mat will be soft and be like new again.
The idea of using the back of the mat for cutting batting and fleece is a good idea too.
I just gently bend the cutting mat over the edge of the table or over a coffee can.
It might not seem like a big deal at first but over time all these grooves add up and can affect your cutting accuracy or worse snag your fabric.
That s all you have to.
I have one old mat soaking now.
Cut the artwork opening in the normal fashion with the mat face in.