It may, for example, be an alcohol such as methyl alcohol or ethyl alcohol, a ketone such as acetone, methyl isobutyl ketone or cyclohexanone, an acetate such as ethyl acetate or butyl acetate, an aromatic hydrocarbon such as toluene or xylene, a glycol monoalkyl ether such as propylene glycol monomethyl ether or propylene glycol monoethyl ether, or a glycol monoalkyl ether ester such as propylene