I have blocked my Roomba’s cliff sensors with aluminum foil (I tried 32 pound white paper, but it didn’t work). It works for a while. After about 5 missions though, the cliff sensors went off again not allowing the Roomba to clean. It appeared that foil had gotten so banged up that it was not reflecting the IR signal of the cliff sensors. The only solution was to remove the foil over the cliff sensors.
I guess the next time I need to clean the black carpet its another 10 minutes work to cover the cliff sensors or just get out the old Hoover.
regards,
John Hansen