can you or should you???
In my experience, if you use a regular (ie 80micron) screen you will see a forgien "film" on the oil when it is a liquid. We scooped it out and it turned out fine, the buds weren't terribly moldy though.
According to graywolf, if you use a small enough micron screen, like he does, you can only get the THC and no mold. The micron is insane small though and I feel like it would be hard/impossible to blow through with a normal tube setup. I don't know shit though.