fred wrote:
After trying wiping with alcohol etc, try attempting to print on a sheet
of paper lightly sprayed with ammonia. Very last resort is a wipe with
an ammonia dampened paper towel.

I've also left the printhead resting in a pool of water for a few hours -
softens up dried on stuff blocked in the jets. (This is the HP type where
the cartridge /is/ the printhead, so a failure just means binning the
cartridge)

Theo