Aluminum cluster anions were reacted with methyl iodide vapor in a fast-flow tube apparatus, yielding primarily I - and clusters of the type Al n I - . Based on thermodynamic considerations, the presence of I - is taken to indicate a neutralization reaction pathway whereby clusters of the type Al n CH 3 are formed. Comparison of relative reaction rates to previously measured electron affinities suggests that the Al n -CH 3 interaction is covalent, rather than ionic, in nature. It is suggested that the neutral cluster complexes reported here may hold potential as high energy fuel dopants.