You can actually use a diamond stone to deburr your skis right at the slopes, by running your stone down the side edges while holding the bevel to the edge. When you file the side edges, you need to secure the skis on a solid surface. Use a heavy rubber band wrap to hold the brakes up off the plane of the edge.
There are ski vises available that will clamp on the edge of a table, but, two sturdy chairs will work almost as well a vise.
Ski edges are not 90 degrees, so, rather than trusting your eye with a free hand file, invest in a variable edge bevel that will hold a file to a preset degree off of 90. Once you know the ski manufacturer's recommended bevel, set the tool, insert the file, and set the flat tool edge against the bottom of the ski.
The sharpening tools and stones you will need are available in most ski shops.
