PREFERABLY WASH LIKE SO...
Wash your jeans in the sink or a tub. Fill a tub with a few inches of cold or lukewarm water. Mix in a gentle, color preserving detergent. Turn the jeans inside out, then lay flat in the tub. Don’t bunch them or wrinkle them. Let them soak for about 45 minutes. Run them under the water to rinse. Hang up to dry.