Residual Solvents in OTC topicals?

Residual Solvents are now being seriously scrutinized by several OTC and Rx companies selling products in Europe. It’s not enough to collect Certificates of Analyses from their vendors, even if their vendors are willing to part with them or if they even exist, it’s the final manufacturer’s responsibility to prove to their clients that their products comply with Residual Solvents guidelines. When an OTC product is manufactured using synthetic ingredients, testing can be straightforward, but what if their products are made with natural components such as oils, pigments and fragrances? Natural components usually have been extracted from one source or another and I ask you, extracted with what?