A refined brightstock oil was deparaffinized to yield (a) a heavy-oil (paraffin) slack wax and the method used to determine the group composition of vacuum residues and asphalts was modified to separate (b) a crude and (c) a refined brightstock slack wax from a Gdansk Refinery vacuum residue. The b-wax as freed from saturated compounds with n-heptane, dearomatized (PAH) with n-heptane-toluene, and freed from polar compounds with EtOH-toluene in a triple columnar chromatography at 80degreesC to yield the c-wax (and the extract). The c-was met the requirements for microcrystalline waxes. The three waxes were studied by SEC, TLC/FID, inverse GC, and simulated distillation using a SIMDIS HT-750 Analyzer. The Flory-Huggins parameter (chi(12)(infinity)) measured in binary systems formed by 29 test compound with a-, b- or c-wax, lower for the c-than for the a-wax, showed the c to be better soluble in the test compounds and to be less polar (as also confirmed by zero interactions in the systems with alcohols as test compounds). The solubility parameter differences between the c- and the b-wax, slight (Deltadelta(2)much less than(MJ/m(3))(1/2)) and diminishing over 80-140degreesC showed the two waxes to become increasingly mutually soluble temperatures.