Before soaking, wash and rinse the item to be treated. The item should always be washed and rinsed after soaking as well. Prior to washing your item, it is always important to check that the item is colorfast.
Dissolve 3 - 4 tablespoons of Retro Clean in each gallon of warm water. Make enough solution to adequately immerse the item. Soak for up to 48 hours depending on the degree of staining. Check and stir periodically. Make sure the item remains immersed. For optimum results, soak the item in a portable container and place outdoors in the sunshine, if possible, as the sunshine helps to keep the water warm which speeds up the process.
One good test is to take a few Q-tips with some cold, warm, and hot water. Test by lightly rubbing the colors in question with the wet A-tip (try all temps) in an inconspicuous location. If the color transfers to the Q-tip, then your colors are not stable and will most likely bleed when placed in a washload.
The item being treated needs to remain just below the surface of the solution. You would make approximately 3 gallons to properly soak a twin size quilt. On the other hand, a hanky could be soaked in a small bowl.
Retro Clean is meant to be used as a soak after normal hand or machine washing. It is usually best to use a portable plastic container, but it can also soak in a sink or tub. It's slow-acting, therefore safe for your vintage fabrics. You would normally soak the item for up to 48 hours. Quite often, the stains are gone sooner.
Retro Clean does not cause fading. In most cases, the colors look brighter as the brown age stains are removed and the original colors are revealed.
Retro Clean consistently removes yellow and brown age stains. This includes mildew stains, tea and coffee stains, perspiration stains, wood oil stains, blood stains, and water damage stains. In some instances, it has only faded grease stains, but just as often, completely removed them.
The rule of thumb is that if an item can be washed in a mild soap, then it can be safely soaked in a solution of Retro Clean.