When it comes to cleaning blackout curtains, a more hands-on approach is required, over the more conventional machine washing method.
First, in the instance where the curtain is covered in a lot of dust, it is ideal to remove it from the window and using a vacuum or a duster to carefully clean the curtain and remove the collection of dust particles.
Second, in situations where these curtains are soiled or stained, it is important to treat the curtain carefully. Removing all rings and hooks, the curtain is laid out straight so that no part of the curtain can cling to itself while it is cleaned.
It is then carefully cold hand washed with a mild detergent to remove stains from the curtain and maintain the integrity and stability of the fabric.
This is, in part, because correct handling of blackout curtains especially, is imperative to ensuring it remains intact. Contemporary methods of cleaning, via machine etc, run the risk of damaging the curtains and can result in losing the effectiveness of the curtain or compromising it entirely. Making it unusable.
What that in mind, careful washing by hand, and dabbing soiled or stained areas with only a small amount of mild detergent is best. It ensures the best possible result for the curtain.