A good whetstone and a little practice will keep all of your knives sharp and in perfect condition. The beauty is that it doesn’t take much effort to learn, just a good bit of practice to get the angle right and keep a consistent angle while you’re sharpening. Whetstones are available in department stores or online, and while they range in price based on the fineness of the grit, this thread at eGullet can help you pick a good grit to start with.
Low Grit Stones: A sharpening stone with grit number less than a 1000 is generally used for knives and tools that are damaged. If your blade has any nicks or chips in the blade, the stones will take care of them in a jiffy! They usually have a coarse side for nicks and chips, with the other side for general sharpening. Even if the knife’s edge has become totally blunt, the stone will re-sharpen it perfectly.
Stropping a knife is a finishing step. This is often done with a leather strap, either clean or impregnated with abrasive compounds (e.g. chromium(III) oxide or diamond), but can be done on paper, cardstock, cloth, or even bare skin in a pinch. It removes little or no metal material, but produces a very sharp edge by either straightening or very slightly reshaping the edge. Stropping may bring a somewhat sharp blade to "like new" condition.
You need the right size of sharpening stone that fit the type and size of your blades and tools. In general, 6-inches stones are the smaller models and 8-inches are the larger ones. The stones larger than 8 inches are work best for big-sized blades and tools. You may also find sort of ‘pocket knife sharpener’ out there. Most of the credit card sized sharpening stone are smaller than 6 inches and ideal for on the go sharpening not for regular basis.
However, due to limited natural deposits and extensive quarrying over the centuries, true, high quality, Japanese water stones are now few and far between and are very expensive. Thus, various companies are now producing synthetic Japanese Water Stones which generally have a more consistent composition and grit size than natural stones as well as often begin somewhat harder and thus, lasting a bit longer; not to mention being cheaper to purchase.
There will be a drawer that extends into the mechanism under the abrasives. Any detritus from the sharpening process drops into this drawer. Exactly where the drawer is located will differ from sharpener to sharpener but it shouldn’t be hard to find. Remove the drawer flick any material into the wastebasket and then wipe out the drawer with a damp cloth or tissue. You may want to use work gloves and goggles to protect your hands and eyes from any loose metal shavings. Once the drawer is clean and dry replace it. The exact means by which the sharpening mechanism itself is cleaned will vary from manufacturer to manufacturer. Consult your owners guide for specific details. Make sure you don’t introduce any grease or other lubricants into the sharpener unless specifically directed to do so by the owner’s manual. Also, the outside of the sharpener should come perfectly clean with just a damp cloth. Avoid using commercial cleaners or abrasives of any kind.
Ease of use – Most people in search of a mechanical sharpener want one because they don’t want to be bothered with trying to achieve a perfect edge themselves using a stick or sharpening stone. They want predictable, first class results every time. In that case it’s important that the electric powered device is easy to use, achieves results quickly and with little effort and is designed with user safety in mind. Keep in mind too that it’s easy to apply too much pressure when using a mechanical sharpener and when that happens you’re likely to see unsatisfactory results. In addition there are subtle differences between mechanical devices designed for Asian-style knives and those designed for Western-style knives. This has to do with the sharpening angle discussed above. Don’t get an Asian sharpener if you don’t need precise control over your cuts.
I've used ceramic rods, diamond plates, and leather strops for our sharpening needs. And, like most, I've tried a dozen little gimmicky sharpeners that, while some work, those that do often remove way too much material from the edge, making your blade wear down faster. I've also used oil stones, grinders and buffers for less meticulous sharpening of axes and such. These two stones from Unimi (600/1000 and 2000/6000) served as my introduction to whetstone sharpening. And I must say I like it. Though, I'm not sure of the need for investing in more expensive stones.
Steeling helps maintain sharpness. This process realigns the edge, correcting for dulling causes such as a rolled edge. A sharpening steel is a type of hardened cylindrical rod used similarly to honing stones. For example, a butcher steel is a round file with the teeth running the long way, while a packer steel (used in the meat packer's industry) is a smooth, polished steel rod designed for straightening the turned edge of a knife, and is also useful for burnishing a newly finished edge. Because steels have a small diameter they exert high local pressure, and therefore affect the knife metal when used with very little force. They are intended for mild steel knives that are steeled several times a day, but are not well suited for today's tougher and harder blade steels. Diamond steels are now available that have an industrial diamond coating and can remove blade metal as well as straighten, therefore used correctly they can re-profile a knife instead of just honing.
One thing about this stone is that it is very "thirsty." I had a cup of water close by just to add a little water periodically when it felt like it was scraping a little too aggressively. Also, be sure to do as the instructions say and use different parts of the sharpening surface. I wasn't paying attention the first few minutes, and apparently I would end each sharpening pass in the exact same spot, creating a very very small notch on the edge of the stone. So I turned the stone around and made sure to vary the ending spot, and it seemed to buff out that little notch very quickly. My knife is now incredibly sharp--it seems to glide through material rather than "cut" it. I know some people would continue to go even higher with the grit, but for my purposes this whetstone is just perfect. I'll be tackling the kitchen knives next!
A: People often make the mistake of assuming that just because a mechanical knife sharpener will sharpen the edge of a knife that means it will sharpen any type of cutting edge, including scissors. This is a mistake and can wind up being a costly mistake when you have to replace both your scissors and the knife sharpener. There are sharpening devices specifically designed to handle scissors. Or you can bring your scissors to a sharpening pro who will usually have the right equipment on hand to also sharpen scissors. Another thing to keep in mind about trying to use a sharpener to sharpen scissors is that by using the device in this fashion you are likely voiding the warranty. As such if you damage the device trying to sharpen scissors you’ll need to pay to have it repaired or replaced as the warranty won’t cover it. Also, certain types of high end scissors also come with a warranty. And, just as with the sharpener itself, if you try to sharpen them using a mechanical sharpener you can say goodbye to the warranty protection. The bottom line is to always use the appropriate tool for the job at hand. That way you’re assured of the best possible result and any warranty remains in effect.