We investigated the effects of adding indium, lead or tin to SmFeAsO1-xFx. It is found that these metal additions to polycrystalline SmFeAsO1-xFx remove an amorphous FeAs phase, which is formed between superconducting grains, and induces clustering of the superconducting grains. Interestingly, addition of each metal showed different effects on the superconductivity. Indium addition increases the magnetic critical current density. Lead addition effectively introduces a large amount of fluorine to SmFeAsO1-xFx. Tin addition enhances coupling between the superconducting grains.