I believe this patent gives the basis for what the aluminum is supposed to do, however looking at whats in this, it isn't the best choice, Zinc or nickle would be better
http://www.faqs.org/patents/app/20090071068
"[0009]The present invention provides hydrophobic metal salts which can be combined with a fire accelerant for preventing, inhibiting and/or removing creosote deposits resulting from the burning of solid fuels. The present invention combines a metal component which provides creosote control, with organic counterions, such as sulfates, nitrates, acetates, etc. which confer hydrocarbon solubility upon the metal catalyst. Additionally, a subset of these counterions themselves can act as corrosion inhibitors of ferrous and non-ferrous metal exhaust systems. Therefore, according to certain embodiments, the composition may contain a metal salt which has a dual role of creosote and corrosion control. According to an alternate embodiment, the composition combines creosote inhibiting salts with corrosion inhibiting salts.
[0010]When an effective amount of metal salts of the present invention are added to an accelerant, the combination delivers the metal catalyst to the lining of the exhaust system upon combustion. The metal catalysts effectively breakdown creosote residue and inhibits the buildup of new creosote deposits, and can also act to inhibit corrosion of metal flues.
[0011]The creosote and/or corrosion control additive composition of the present invention comprises a hydrocarbon soluble transition metal salt, having a chemical structure of the formula:
X+m[Y-n]p, [0012]wherein X is a transition metal having an ionic charge of +m, [0013]Y is an aliphatic anion, having a charge of -n, and [0014]m=pn.
[0015]Preferred transition metals include Mn, Zn, Ti, V, Cr, Fe Co, Ni, and Cu; with Mn being the most preferred. Other possible transition metals include, but are not limited to Zr, Mo, Ru, Rh, Pd, Ta, W, Re, Ir, Pt, Au and Pb. Other transition metals may also be possible, as will be understood by one skilled in the art, but the above mentioned are believed to be the most ideal."