Boy,, this is the same torture I went through with the top of the line Canon color inkjet - it sat several months while in Europe,, and just when it was needed,, it's now down to a new print head,, a bit spendy last time I checked.
I also tried the rescue treatment with alcohol,, and no luck. He was such a great printer, actually blew me away.
Best of luck with this issue.
Cheers