The solubilization of solutes in surfactant aggregates (micelles) is studied using lattice-based Monte Carlo simulations. Various properties such as the size and shape of the micelles, the critical micelle concentration, the locus of solubilization, and the partition coefficient of the solute are obtained, and the implications of the results for the thermodynamics of solubilization are examined. The presence of contaminants in the solution affects micellar properties by promoting micellization and stabilizing micelles. The ratio of head group size to tail group size for the surfactant is found to greatly affect both micellar properties and contaminant solubilization. The partitioning of the solute is found to be independent of surfactant concentration, but increases with solute concentration. The results show that contaminant partitioning is controlled primarily by enthalpic contributions.