Originally Posted by romanojg
If you wash it it will be lumpy. My daughter did that to mine and she even took it out so that the machine was large enough to hold it. A 150 comforter in the trash; can't fix the lumps
Most likely the lumpiness was caused by machine agitation. Polyester batting that isn't needle-punched or treated with bonding agents can't take machine agitation. (Top loaders are hard on all kinds of quilts.) Most likely many of the commercial comforters have this kind of batting.
I think I would still take a chance and wash/dry myself rather than dry cleaning. However, I would use a top-loading washing machine and do all the agitation by hand. The method requires filling the machine with soap and water, turning the machine off, adding the comforter, hand agitating by pushing down on the quilt, turning the machine to "spin", adding rinse water, turning off the machine, hand agitating, turning the machine to "spin", etc. The idea is to skip all the machine agitation cycles of the machine. Spinning is not hard on a comforter the way that machine agitation is.
With a commercial comforter, I would not trust even the milder agitation of a front-loading machine; if the batting is polyester without needle-punching or bonding agents, I would be afraid that even that much agitation would cause the batting to lump.
It's probably a good idea to search the comforter for a "contents" tag. If there's a lot of rayon in the comforter's fabric, that might be another problem for washing because rayon can shrink a *lot*. I would not be as concerned about primarily cotton fabric shrinking. The biggest problem is the batting, I think.