Pesticides residues causing rejection of many consignments of spices which are being exported from India. So if we are able to reduce the PR levels post harvest through any treatment, then we can earn much revenue through export.
The best cost effective method is to collect raw materials which has no or minimum pesticide residues in it. For that you can implement Good Agricultural Practices in your fields.
No, any attempt will compromise the spice or be ineffective due to adsorption of UV. Get spices that are pesticide free if you cannot stomach the biocides.