Ok, I have to chime in.
Like many of the characters on this board I spent a certain portion of my youth cleaning bike parts in various industrial solvents. One by one we would hear that the solvent de jour was implicated in causing cancer and then we would switch to another. Benzine (not gasoline in the US), xylene etc. Why we never settled on heavy rubber gloves and good ventilation. I don't know.
Skip ahead to the early 1990's when I was manager of process engineering in an aerospace plant. We did a lot of cleaning of metal parts, especially prior to adhesive bonding. At that point I used to able to clean my bike parts in what is called a chemical vapor degreaser. This machine heats the solvent, vaporizes it and then uses a cold layer on top to trap the vapor. Parts cleaned this way are absolutely stripped of grease and dirt. However, these devices became regarded as environmentally unsafe and we had to find new alternatives.
After a great deal of study, what was installed- giant industrial dishwashers using detergent. Like Dale suggested. This proved to provide better results in every respect compared to solvents.
Please be careful about using flammable cancer causing solvents. If gasoline didn't power cars, it would be tightly regulated.
Joe Bender-Zanoni Great Notch, NJ (Where they wisely rquire that a professional pump your gas)