P**12 is high priced, re-packaged butyl acetate, sold in plastic bottles which cannot prevent the vapor pressure of the solvent from dissipating into thin air, thereby creating the need to buy summore before you've ever had a chance to use it all.
Go down to the hardware store and buy a can of Weldwood Contact Adhesive Cleaner (butyl acetate), or if you're concerned about flamability, get a can of Energene Cleaning Fluid (a chlorinated hydrocarbon solvent). Either one will clean anything that is soluable in a *hydrocarbon fluid*, and do it very well without harming the photographic emulsion. It'll also last for years in that metal can.
It's important to remember that hyrocarbon based solvents can only remove oils, marking pens, waxes, resins, tallows, and similar *hydrocarbon* based contaminants. They cannot remove mineral deposits. The only way to dissolve lime (calcium carbonate) is with an acid. A strong one at that. Not suggested.