I use the self-healing Olfa mats. I have had a large one for a couple of years. I clean it often with a soft brush to remove dust, lint and debris and have soaked it a few times. I recently purchased another Olfa mat and butted them up to each other on my long counter. When cutting a fairly long piece of fabric, I noticed my rarely used blade had 'skip' sections on my cutting line, but only on the old mat. I tested several other fabrics and changed to new blades and had the same problem. I wiped off the mat with my hand and slightly deeper cut lines in the mat. It occurred to me that the blades were skipping as there was no flat smooth hard surface for the cutter to go against. I used a kitchen brush that has the green microfiber pad on it and gently went over it a couple times. That did the trick. Blades glided right over and cut perfectly. My blades were acting dull, but they were not the problem.