Carefully cut the caulk away on the top and bottom of the caulk line with a razor blade. Grab the caulk with a pair of needle nose pliers-- it should come out as long strips. You might have to use the razor to scrape off remaining bits of caulk. A hair dryer on low heat can help soften the caulk. Clean well, make sure it is dry and put blue painters tape down to mask the sink and counter before reapplying new silicone. I think you can use acetone but you might want to ask a fabricator/stone yard about that.

I just did this a couple of months ago, I used a curved paring knife and was very slow and deliberate. It can take forever but it is important to get as much of the old stuff out as possible. Our installer initially used clear caulk and it started looking cruddy very quickly so I replaced it with white. It is amazing how big of a difference crisp, clean caulk makes.

sharp new razor and steady hand. before you redo it, clean it with mineral spirits, and rub with a microfiber cloth the get rid of the little bits that are tough to see and like to stick. use a more appropriate calk, it sounds like they either did not clean the grease that all metal sinks have after manufacture before caulking or they used the wrong material.

three3apples:

Stop by a cabinet shop that does plastic laminate. Pick up or have them rip some strips about an inch wide. When you break off the end of the strip, it will make an edge sharp enough to cut caulk but dull enough not to scratch anything. Keep breaking to keep a sharp edge.

Avoid metal for this job, unless you'd like to do a scratch repair.

The caulk that does the work should be between the sink flange and the bottom of the top. Check this, please.

It's been almost a year, started peeling off after just a few months. I've had so many things going on I've not been able to keep up with all of it.

I will try to find a cabinet place that does laminate.

I was planning to put the new caulk in the same place as the current caulk, just forming a seal between the two.

Is there a preferred brand that will perform better than whatever I have? My sink is white cast iron, the counters are white marble.

Thanks for all the tips! I plan to do this sometime in the coming weeks and will repost with a report when I'm done.