Same way you'd clean anything else made of the same material.
Silicon (tips) : warm or hot soap and water, or dishwashing liquid (something antibacterial is good). Wiping them down first with isoproply alcohol is always good.
Foam (tips) : same way but no isoproply alcohol. With foam make sure to rinse 'em really well. Squeeze the water out of them a few times in the process and rinse until your sure there's no residual soap remaining. Squeeze all the water out of them and let 'em air dry, No heat.
Anyway, that's what I do. Some folks may do it differently - whatever works.