An new class of oil-soluble, sulfur scavengers or converts are disclosed where the scavengers include substantially monomeric aldehyde-amine adducts from the reaction of at least one sterically hindered primary or secondary amine and a molar excess of at least one aldehyde. Methods are also disclosed for reducing, reducing below a given level or eliminating noxious sulfur species from fluids using the inventive scavengers and for making the inventive scavengers.