The silicoil is used at the end of the day and evaporates by the next morning. If there is any residue, it would be so small as to be negligible. Just as a precaution, though, he rinses the brush in clean solvent before using, but it probably isn't necessary. As to it being either kerosene or expensive, it sure doesn't smell like kerosene and it's about $4 for a 16 oz bottle that can be used repeatedly and lasts for quite a while. I'm not really sure what it is that you're worried about, since all of the solvents commonly used by artists evaporate without permanent damage to the paint film. If I'm not understanding correctly, please explain what you mean.
BTW, back to the soap and water issue, any time natural hair bristles come in contact with water they swell and their shape is affected, leading to the splaying that Brad first wrote about. Steven wants good, sharp points on his brushes and, using the methods outlined before, they stay that way.
