How do you wash a white comforter that has other colors that could bleed into the white part?

I'm not sure how to wash this comforter. I've read reviews that someone washed the same comforter and the purple flowers and designs bled into the white.How do you wash a white comforter that has other colors that could bleed into the white part?
I would use cold water so the colors won't bleed, but if you read the tag on it, it will tell you if the color will bleed or not. Usually before selling a product that has fabric, they will wash it before packaging. You could also take it n for dry cleaning so that you know they'll be caareful with the fabric.How do you wash a white comforter that has other colors that could bleed into the white part?
You can test the colors before washing by taking a white towel, dipping it in a bowl of warm water in which you dissolve some laundry soap and rubbing lightly for a few seconds on each different color. If the color comes off on one color or more, it will bleed in the wash. It still may bleed even with the test but if that is the case, you are just out of luck. Dry cleaning may be OK depending on the dye and the type of fabric. Cold water or adding vinegar will not really stop any dye bleeding if it is going to happen. And to the other answer, manufacturers do not wash ';new'; bedding or clothing before selling it. That is wishful thinking!
You can safely wash this comforter by machine washing on delicate in COLD water only. Make sure you have machine on cold/cold cycle. Then, either hang to dry or dry it in the dryer on the fluff/air setting, or whatever the lowest/coolest setting is on your dryer. It is heat that makes colors bleed. Good luck.
Spot treat any difficult stains with a mixture of detergent (liquid) and water. When you do wash the comforter, use cold water to avoid colors bleeding. Also, line dry it so it keeps its shape.
Try using Woolite and soaking your comforter.
follow the manufacturer's instructions -dry clean or cold water wash.
wash in cold water with baking soda (1 cup will do) and some woolit
wash it, cold water, by itself or with other white clothes
wash it in cold water
dry clean only!