I was doing a bit of maintenance on my 5th gen the other day bofore a longish ride, and started thinking about renewing my brake pads as feel and performance had seem to be a bit shit lately. I removed all the pads (EBC sintered) and realised there was still a lot of meat on them. I placed some rough emery paper on a flat block of steel and proceded to give them a good rub down. I also washed down the disks with a scourer and brake cleaner. Reasembled it all and went for a ride a few days later. What a difference, it was like having a new brake system. Feel and bite was excellent, as was stopping power. Before this, the rear brake pedal did nothing, and front had no initial bite. Now they are actually good, and has stopped me from thinking of doing a de-link.
A brake tune up should be done periodically to remove glaze from pads and clean road grease from the rotors..........as you discovered. Pad glaze looks like a grey film on surface. Rotor oil can be spotted by running your clean hand over the rotor. I prefer a fairly agressive approach and sand both pads and rotors with #400 sandpaper, spray off with brake cleaner (don't allow any to contact the tire !!), and do a quick mini-bleed (one squeeze into a rag over the bleed nipple) on every bike about once a year. Helps to clean and regrease caliper slider pins yearly too.
