EPSON R300 inkjet printer Ink Waste Pad Full.
(By the way this applies to these printers too - Epson R200, R210, R300 and R310)
After doing many head cleaning operations I got an "error" from my Epson R300 and this error would not go away by switching the device off/on.
Looking at the maintenance manual this was in fact the counter for the head cleaning operation reaching a certain internal number. This can be reset by pressing 3 buttons ( “Stop”, “Maintenance”, and “Power” ) together for about 10 seconds or so. You will know when it has finished as the printer will ask for a power off. If your printer has no display panel just switch off after about 20 seconds or so. Hopefully when you power on the printer the error should have been fixed.
This leaves you with the problem of the absorbant pads probably saturated with ink. Do not bother trying to replace the pads. At the back of the printer there is a tiny flap (about an inch square). Via that flap you need to locate the access ink exhaust pipe and feed the pipe to the outside of the printer, small pair of tweezers came in handy. I drilled a small hole in my R300 and fed it to a small jam glass jar (you can use any suitable container). Tied this to printer using a plastic tie wrap and a sticky pad. You will need to make a hole in the jar to feed the pipe, I made an extra hole so air can escape.
You will need to check the ink level every few months depending on how much you use the printer. You can empty your container when necessary.
Hope that helps someone.