With our first child on the way this could be oddly useful!
Congrats! +1 on the newspaper walls...
Lennon's medicine contain about 80% alcohol - that's why the old folks liked it so much, so maybe that's what did the cleaning trick. Try some "witblits" also, maybe that'll work. ?
While on this topic: I recently found that acetone is good for cleaning lots of things, from glue to paint. Haven't tried it on Koki but I suspect it will work.