I love to make charms and i found that using just a drop of scented oil will work nicely. It wont last forever though, but rubbing the charm helps bring out the smell. I've searched around the internet to see if i could find better ways but it seems that oils and add ins such as herbs and spices work for the most part, i also read(but never tried) that alcohol based fragrance wont work at all. there are alot of sites that can help goggle was a big help for me.