That sounds kind of icky. Stick to water and detergent. Diesel contains several hard-to-remove things. Basic old hydrocarbons - detergent and hot water Parafin - detergent, agitation, hot water Dyes...
If they have been dried, it's probably too late to do anything. You can wash them again using a cup to two cups of bleach or there is a product available that removes dye. Should be with the laundry...