When we built the house in '74, the contractors decided to finish our garage walls and ceiling with the same thin-coat plaster/sand texture that they used inside the house. I've regretted that ever since. We have an opportunity to fix the issue this summer, and I'm wondering what's the best way to smooth that texture out. I don't necessarily need to take it down to perfectly smooth, just enough to not catch quite so much gravel dust as it moves across from the road. Suggestions??