@rundocuri- I have a vacuum with a reusable filter, and it is not hard to clean at all.
If your filter isn't too dirty, all you have to do is take it outdoors and shake it very hard. This will usually release the dirt that is caking up the filter.
On the other hand, if your vacuum filter is very caked with dirt and grime, you may have to wash it for the best results. After you shake off any loose dirt, clean it under running water with some mild soap. Rinse it until the water runs clear, and set it aside to dry. Don't put it back in your vacuum until it had dried thoroughly, or you will cause it to cake up with dirt again when you run the vacuum.