Is the sucker still under warranty. If so then canon is very good
about sending out replacement heads. The warranty is usually 1 year
but other nations have a longer one.
If that's a no go you might want to explore this thread
http://www.nifty-stuff.com/forum/viewtopic.php?id=63
I tried putting Salmalki in a bag with a bj2100 printhead to see if
that would clear the clog, but seems the Ammonia Chloride isn't strong
enough to release fumes.. unless your eating it or kids spit it out on
shallac.
The most interesting technique is the use of ammonia based cleaner
(Windex, Windolene, blue glass cleaner) with toilet paper foled over,
placed in a dish, and saturated with solution. Pressing the printhead
down on the saturated paper forms a seal which causes the solution to
be pushed up into the chambers. The person who used this technique
reccomends a slow push and a quick pull, and after 10 or so times
replace with fresh paper and a fresh solution. Eventually this will
get all the ink out of the printhead and your left with a cleaning
solution which will in theory over time solve a clog. This might
require sitting in a solution overnight or two nights.
Others might reccomend a solution of alcohol and windex, still others
reccomended dilluted ammonia or a tiny bit of ammonia added to a windex
alcohol solution. There are commercial cleaners on the market that
cost a tad more which you can buy from your usual 3rd party ink
resources. I bought some stuff in a refill kit that cleared a
printhead clog in a disused bj-2100 that had been sitting for a year in
under 15min.