I would try a good soak in oxi-clean free (unscented kind). Now, the label says to
not use on wool....so maybe do the new pants first to test what will happen. I have never tried it on wool, but have never seen any deleterious effects on any number of materials (including a 5 min scrub on the dogs after they decided that black&white striped cat looked fun to mess with).
Fill the wash tub up to the top with water/clothes and the dump in a bunch of oxi-clean. Let the tub agitate for a few minutes, then open the lid or otherwise stop the machine from running. Let this sit for an hour or more, then allow it to resume.
The key here is the soak, don't be afraid to let that sit for awhile....it's a chemical reaction (oxidation) and does take time.
Other than that, time airing everything out would work too. The smell is a result of the chemicals in moth balls sublimating (going from a solid state to gas). This reaction continues until all of the solid residue turns to gas, and then there will be no more smell...but this too takes some time (maybe a month or more hung up in a tree outside).