Correction fluid the Montreal Protocol on Substances That Deplete the Ozone Layer, and then the slightly safer trichloroethylene. Thinners currently used with correction fluid include bromopropane. Because it contains organic solvents (volatile organic compounds), unused correction fluid thickens over time as volatile solvents escape into the air. It can become too thick to use, and sometimes completely solidifies. Therefore, some manufacturers also sell bottles of solvent as "thinner", a few drops of which will return the correction fluid to its original liquid state. To avoid the inconveniences of organic solvents (safety and availability), some brands of fluid are water-based. However, those have
Wiley protocol at separate times throughout the period. The protocol is promoted as differing from conventional hormone replacement therapy in several ways: The protocol also includes a follow-up program to monitor the serum of the bioidentical hormones. Wiley has stated that in her opinion, the most important aspect of the protocol is the specific schedule and levels of the hormone doses rather than their bioidentical nature. A patent was granted for the protocol in 2011 for the specific blend of hormones and dosing method. Concerns have been raised that serum levels may not be an acceptable marker for transdermally administered hormones, that