First you can "clean" your lead with a small chunk of wax about the size of a pea,,it acts like a rosin. Next comes the "heat factor" Wrinkly sinkers generally come from the mold being to cold,,,I preheat my mold on the other burner on my propane stove. Sandy or crystaline looking sinkers come from your lead being to hot. You can expidite your process by opening up the pour hole on your sinker mold with a round file and opening up the hole a little at a time until it suits you. Making sinkers release from the mold is pretty easy too,,,just spray the mold with a silicon spray or even a vegetable oil like pam will work --- cast a dozen or so and reapply.
Catfish and new shiny lead sinkers,,,well I have a theory about this...I think they can smell the lead and may even be warded off by it. So you can do a couple things to seal your fresh lead,,,one is leaving them outside to "age" and get that dull oxide coating which doesn't readily disperse into the surrounding water. The other is coat or paint your sinkers,,,no no not the krylon in a can stuff---use parafin wax,,,heat your sinkers in boiling water, heat your wax until it's a liquid and dip then set aside....something I'm gonna try as it cant hurt attitude is flavoring your "hot wax" with oils,,,what oils,,,I think I have given out way to much information att