So, I finally got tired of buying rebuilt laser toner cartridges for my multifuntion printer and decided to see if I could add toner to recharge them and save some money. Long story short, I found Oasis Imaging Products, and they provide instructions on how to rebuilt laser toner cartridges on their web site. Go to: OASIS IMAGING PRODUCTS and click on the "Click here to view our cartridge instructions" link on that page, simply find your cartridge alphabetically. For example, my Canon MF3240 multifunction printer uses a Canon X25 toner cartridge, which is one of the most common cartridges in Canon laser printers. So, I left click on "C" for Canon, and go through the first, second and third pages before finding instructions for the X25 on the fourth page of Canon cartridges. And here it is; the instructions for rebuilding my toner cartridge: http://www.oasis-imaging.com/images/pdf/cart_inst/CanonX25.pdf And, so far this month I've rebuilt one X25 toner cartridges with new parts, and simply rebuilt a second toner cartridge by just cleaning the old parts and adding new toner. It's really not that hard. It costs about $25 to rebuild it with new parts, or just clean out the old toner and add new toner for about $5 and reuse the old parts. I tested both cartridges, and they're both working perfectly. Some notes on the rebuilding procedure that weren't spelled out in Oasis' instructions: 1. Never touch the OPC roller (Organic Photoconductive roller or "drum") with your fingers because the finger prints you leave can cause toner to stick to the drum's surface, and screw up your prints. Whenever you work on a toner cartridge, you should be wearing latex or vinyl gloves. And, don't use any cleaning chemicals like detergents. The best thing to clean with is a clean, dry cloth and/or compressed air. But, you can also use isopropyl alcohol to clean any of the rollers or wipers. (In fact, I use isopropyl alcohol to clean the mylar wiper blades, and it works very well.) Isopropyl alcohol comes in both 70% and 99% concentrations. Buy the 99% stuff from any pharmacy. 2. The supply hopper has a magnetic roller going through it. It is driven by a gear at one end and is charged to about 600 volts of static electricity at the other end. It turns out that both ends of the magnetic roller have a "D" shaped cross section instead of being round (or at least that's the case in the Canon X25 cartridge). I had some trouble getting the end cap back onto the supply hopper, but it was only because the "D" shape of the magnetic roller end wasn't lined up with the "D" shape of the hole it was supposed to go through. They don't make that point clear in Oasis' instructions. 3. When I first tested the first cartridge I rebuilt, paper wouldn't go through it, and I got a message reporting a paper jam. Actually, what the problem was is that I didn't lubricate the wiper blade that wipes excess toner off of the OPC roller. Without that lubrication, the OPC roller won't turn, and the entire cartridge will behave like all the moving parts inside it are seized. The way to lubricate that wiper blade is to simply save some of the unused toner from the supply hopper. Fold a piece of paper in half lengthwise and deposit a bit of that unused toner into the crease. Now, run the wiper's mylar blade back and forth over the toner to get a generous amount of toner on it, and then install it in the waste hopper. Then, after putting the other parts in the waste hopper, rotate the OPC by the gear at it's end to make sure it's rotating freely despite the mylar wiper pressing against it. The OPC drum will be easy to recognize because it'll be either red, blue or green. It's the most sensitive part in the cartridge. You don't want to touch it with your fingers or scratch it's surface. NEVER expose it to direct sunlight or UV light. Keep it in the dark whenever possible. You won't ruin the OPC by exposing it to fluorescent or incandescent light for a few minutes, but if you leave it out for a week or two, it'll be toast. They sell special chemicals to clean this roller, but you should be able to get everything off of it with a soft dry rag, compressed air, or if necessary, a rag dampened with isopropyl alcohol. There's also a PCR (Primary Charge Roller) inside the waste bin along with the OPC. It's the least sensitive roller in the cartridge. You can wash it with soap and water or clean it with isopropyl alcohol. In the opposite side of the cartridge, (in the supply hopper) is a magnetic roller. You should try to avoid touching it to prevent getting finger prints on it too, but it's not sensitive to light, and you can clean it with isopropyl alcohol, dry rags or compressed air. There's a mylar wiper on both sides of the cartridge. The one in the supply hopper side is called the "doctor blade". The one in the waste bin is called the "wiper". In both cases I find that cleaning them with compressed air and then with isopropyl alcohol doesn't do any harm and results in better performance than putting them back in without cleaning with isopropyl alcohol. Officially it's best to lubricate both the doctor blade and the wiper with toner before installing or reinstalling them, but the only one that's critical is the wiper in the waste bin. Without lubricating the wiper in the waste bin, the cartridge will behave like it's seized up. If you don't lubricate the doctor blade, the cartridge will still work, and the doctor blade will get lubricated after the first couple of pages printed. Essentially, rebuilding a toner cartridge consists of replacing the: 1. OPC roller 2. the doctor blade 3. the wiper in the waste bin, and 4. replacing the toner in the supply hopper and cleaning the old toner out of the waste bin. However, you can reduce your costs significantly by only replacing the toner and cleaning the other parts. The only parts that will wear out are the OPC roller, the doctor blade and the wiper in the waste bin. The OPC roller is only good for about 3 cycles, but the doctor blade and wiper are good for a dozen or more. Typcially, the OPC roller will cost you around $10, the doctor blade about $5 and the wiper in the waste bin will be another $5. The toner is sold by quantity. My cartridge takes 150 grams of toner, and that costs me about $5 too. And, after testing both of the cartridges I rebuilt myself, the print quality is equivalent to what a new cartridge would provide. PS: Don't have anything to do with anyone who wants to sell you a bottle of toner and some kind of tool to drill or melt a hole in the cartridge to add the toner through. That's bogus. In my cartridge there is a paddle (similar to the kind on a riverboat) that rotates with every page printed, thereby redistributing the toner uniformly along the width of the cartridge. If you drill a hole in the supply hopper and then plug that hole, you'll have to make sure that the paddle doesn't hit that plug. If it does, you've got to either use a shallower plug, or try doing it the proper way by taking the cartridge apart. If you take the cartridge apart, you'll find there is a hole in the supply hopper which is fitted with a plastic plug. The people that rebuild toner cartridges for a living will remove that plastic plug, clean out the old toner and add new toner through that hole. So, you don't need to make any holes. There's a hole there already, you just have to learn how to take the cartridge apart to access that hole. And the instructions on the Oasis web site allow you to do that.