The question of what to clean a movement with comes up frequently. There are a number of adequate ways to clean a clock movement and I am not here today to push any one method over another. I have a warning to give the unsuspecting novice as recently found out by someone I know. When a movement comes in so dirty you do not want to foul your expensive cleaning solution or one wants to clean a movement without affecting the lacquer many point to a solvent such as lantern fuel, mineral spirits, white gas, VM&P, and others. Any of these will clean dried gunk with a little soaking and scrubbing. However, be aware things are changing. In California, Texas and other states there has been a push to reduce VOC's (volatile organic compound) emissions. In California and Texas industry cleaners are supposed to have 30% VOC or less. VOC's are petroleum bases such as mineral spirits, White gas, etc.. Recently a newbie asked about cleaning a very grungy movement. He has a sensitivity to strong smelling chemicals so I told him to go to a Big Box store or paint store and get some "Odorless Mineral Spirits", commonly referred to as OMS, it's the same thing charcoal lighter fluid is made of. He called after buying it and putting the movement in and asked if it was supposed to be white. OMS is colorless. He pulled the movement and then put it in a regular ammoniated clock solution. The result is below. What he actually bought was one of these Low VOC products labeled, "Low Odor Mineral Spirits." which only contains 30% mineral spirits. The rest is water and some chemicals that keep the water and oil in suspension. I manufacture such a product for use in a particular industry so I know what is in there. Some of these compound are not friendly to brass or bronze. The point of this post is, be careful what you get. Read the labels if you are buying something you are new to. I believe I can salvage this movement but it will require some time that otherwise was not necessary.