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. 

Unfortunately, the arrays of modern whetstone can be bewildering to the inexperienced sharpeners that so often times many of them end up with a crap or wrong decision on stone type for their utensils. The most difficult to determine is whether the whetstone is fake or fabricated with low quality of materials. To avoid this you can only go for the reliable brand of a whetstone.

Now you may wonder, if a finer stone produces a better cutting edge why do I need a coarse stone at all? The answer is that finer stones work much more slowly than coarse ones. The amount of metal a fine stone removes with each pass is much less than what a coarse stone removes. If you have an edge with a good shape to it from a coarse stone, this is not a problem because the fine stone doesn’t have to remove much metal to improve the edge. If the edge is dull, it will take many times longer to reshape it with a fine stone than it would with a coarse one.