Base repair is a fairly simple procedure for most minor gouges that kidz will put in a base.
Here's are some great base repair guides, not much to add to them:
It really is simpler than flat filing the base, save some moneys and do it yourself.
The melting candles are easy to use and good for shallow gouges. The repair ribbons that use an iron to melt in are a lot more durable though.
If you melt ribbons, use an iron that will not heat too much. Fluoro waxes in the base, heated at more than 1000F will generate a very toxic gas! Ski Racing Mag
Read on for even more Ski Tuning Ideas.