If you’re confident at opening and cleaning the remote, best bet is to get a used one from Ebay and give it the cleaning routine alongside yours. Then you’ll have a spare one to use if the other starts to fail again. It’s also worth checking the lens on the 1100’s casing; if that’s dirty the fault could be there although the remote is far more likely to be the culprit.
Take it to pieces and clean out all the accumulated greasy gunge. If necessary, add sticky-backed aluminium foil or conductive paint to the rubber keys.