Originally Posted by AngryAndy
I know it's more work but just before bottling could I heat up the priming sugar and rack the beer from secondary to a third bucket (leaving the sediment at the bottom) add the priming sugar and bottle it?
Yes, that is the proper technique.
You will rack from the carboy from above the sediment, and transfer the beer by siphon to the bottling bucket.
First, boil a cup or two of water, add your priming sugar to that and boil for a minute or two. Then, pour that into your sanitized bottling bucket, and start your siphon from the carboy. Put the tip of the tubing on the bottom of the bottling bucket, in a circle, so that the beer flows into the priming sugar in a circle filling from the bottom up, to mix the priming sugar without oxidizing the beer. You want to avoid any splashing or agitation of the beer at this point.