how to find original solder seam?

Hi all

how would you go about finding the original solder seam on a ring/bracelet, either to cut to resize or just to experiment (like myself)
Think i remember somewhere that you heat on oxy rich flame and quench...is that right?
any other methods?

Thanks

Too oxy rich might cause damage, so not too sharp a flame. Work in a darkened area and as soon as a faint glow appears, quench Dennis