Plus, the quilt dries quicker, reducing the chance of mildew and drying streaks. If your quilt is very stained, it may help to spot treat areas before washing the whole quilt. Old quilts are made of natural fibers which absorb easily. That's why there are white glove ladies at quilt shows - they are there to protect those cotton fibers from body oils, liquids, soils, and other organic substances. Over time, these invisible stains oxidize to colored stains.
Antique quilts face other problems, too, like molds and bugs.
The scattered spots known as foxing is damage resulting from these growth of molds. Often what we think of as blood stains or rust stains are actually what is left of a dead bug. These stains are nearly impossible to remove. Many quilts folded and stored for years will have brown stains that often look like furniture polish, blood or rust but are actually caused by dye migration. Changes in temperatures can cause this to happen and most stains caused by dye migration cannot be removed because the dye has permanently stained adjoining fabrics.