Don't know if you tried this, but with charms, just soak them in the sink, if you must prewash. You can put a color catcher in, with hot water, a squirt of detergent, swish and let soak. Rinse and lay flat on a towel to air dry. Then you won't have all that mess to deal with from the agitation of the washer or the tumbling in the dryer.
Just a thought.