Yep, should always bottle from a completely clean/clear container.
When you do rack to a carboy or fermentor bucket for bottling, the slurry left over in the originating carboy can be processed as DUGGER said.
Actually, I always save the slurry left at "every" racking, so I can recover the little bit of wine that will settle out. Sometimes it turns out to be more than a little bit, other times there is so little it is not worth saving.
For my purpose, I use a large glass jar, made for holding spaghetti. It has a large mouth and a nice sealing lid. (Any sealable, clean, clear container can be used.) I put all the slurry in it, seal it, and let it set for a day or two. After it settles, I carefully siphon off the top portion and use it for a taste test or put it into the receiving carboy to top off.