Method #3: Dishwasher Paste
To get a little more direct focus on those stains, you have to give them all the concentrated power of your dishwasher detergent. The best way to do that is to make this paste, which uses dishwasher detergent to really break down stubborn stains.
Combine dishwasher detergent and hot water to make your paste. Rub this onto the stains and let it sit for a while. After about thirty minutes rinse off the paste and see clean, stain-free plastic.
From: tiphero.com
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