This works on Canon printers with sponge-filled ink cartridges.

First of all, buy some QUALITY ink. Here is were you can get it. http://www.re-inks.com/ Get a refill kit for your printer.

Some Canon cartridges are easy to re-load, others are slightly trickier.

Fill a syringe with the color ink you need. NEVER use a syringe for more than one color. Once a syringe is used for black ink, mark it BK for black and use it ONLY for black ink. If the cartridge has a seal, remove it and refill the cartidge in the obvious way. Then insert a re-usable seal.

If the cartridge can not be opened easily, do this: Turn the cartidge upside down and slowly drip the ink into the sponge filler. When it will not absorb any more, you are done. Turn cartridge right side up and prepare for some dripping, so have a paper towel handy. When the dripping stops, wipe off the cartridge and it is ready for re-use.

At our office, we save 95% compared to buying new cartridges.