Solvents such as glycols, such as propylene glycol and polyethylene glycols of different molecular weight; ketones, such as methyl isobutyl ketone, methyl isopropyl ketone and cyclohexanone; amides, such as dimethylformamide or diethylformamide; N,N-dialkylated carboxamides; alkyl lactams, such as substituted pyrrolidones and caprolactams hydrocarbons; n-paraff ins and isoparaff ins having differe