After removing a spent cartridge from your printer don't just throw it in a drawer and expect to be able to refill it in a month or even a year, judging by some of email I get.

The main reason why sponges dry out is because of a special drying agent that is added to inks. This drying agent is used to prevent smearing when you print out a page. When ink is inside cartridge, especially an unsealed cartridge, it will react with air and harden sponge. When ink in cartridge is used up it is displaced by air which is trapped in cartridge. In a few weeks or even days ink left in sponge will harden to a rock like consistency.

Many people think that a refilling business is type that people bring you their cartridges, you refill them, and they pay you and leave. That's hard way to do it. A much easier way is to obtain empty cartridges, refill them and sell them. The trick is where to get empties so you don't go broke in process. Another thing to realize is you only want to refill cartridges that have print heads on them. Most HP and Lexmark cartridges fall into that category. Most Canons and all Epson's won't.