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This can be a clean bathtub or large laundry basin. Make sure it is big enough for your blanket and required volume of water.  Don't fill up the tub too much. You will want room to be able to move the blanket in the tub without spilling water over the tub. Have the tub at an appropriate height if you have trouble bending over. Avoid leaning over a tub if the blanket will be too heavy for you to lift when wet. Avoid harsh chemicals which can damage the fibers of the fabric and cotton filling. This includes bleach or other whitening agents.  Gentle detergents and thoroughly rinsing your blankets and covers keeps the fabric soft and comfortable on your skin. Use an amount of detergent suitable for the size of your blanket. Between half to a full single cupful (the cup of your detergent container) should be adequate. Use a sloshing motion to activate the detergent in the water, making it frothy. This evenly spreads the detergent throughout the tub, giving your blanket even soap coverage when washing it. Push the blanket into the water to completely cover it in the soapy water. Use your hands to gently knead the blanket in sections so you know where you have cleaned. Leave the blanket in the tub and drain the water from the tub. Once the original soapy water has drained, add clean water and rinse the blanket. Do this repeatedly until there is no soap residue left on the blanket.  Swishing the blanket through the clean water will help dispel the soap from your blanket. You will know if the soap has been removed when the rinsing water runs clear. Squeeze out the excess water from the blanket by rolling it tightly. You don't need to wring it out. Do this repeatedly until most of the water has been dispelled.  You can roll or fold the blanket and press on it to squeeze out the water. You will not be able to get all the water from the blanket, which is normal. Wringing out your blanket could misshape or redistribute its weight, so squeezing is the best option. Lay it out in the sun or over a banister. Shake it out every 30 minutes to shake out excess water and redistribute the weight. These blankets are  designed to provide additional levels of comfort via evenly distributed weight and gentle pressure, so keep them as even as possible.
Fill a tub halfway with tepid water. Add a mild detergent to the water. Run your hands through the water. Submerge the blanket completely in the water. Pour fresh water into the tub. Remove the excess water. Dry the blanket.