They can work real well; so can crappie nibbles. Any time of the year. I generally have better luck with live waxies, spikes or some of the tiny plastics. One of the best is live goldenrod larvae from what I hear, but I have never actually used them myself.

Small jigs, even 10s are a little big at times, light lines, like 2#, locate fish signals on your flasher or depth finder before you fish a hole and then start from the top down all the way to the bottom and then slowly, little more than twitches, work your way up. Watch your flasher or depth finder for what kind of fish responses you get. Don't be afraid to change out the bait or move. If you have a shack, you may and often are able to look right down the hole and watch what happens.

I generally do alright on GULP but the smell gets to me; so they become my kitchen sink. I will certainly take the smell if that is all that will get me fish. The 1" GULP ALIVE minnow baits do even better than the waxies but are too much mess for me on the ice, what with the juice and all. The 1" leeches are also very good - black is best from me with those. If you have the ALIVE version with all that juice, a tweezers to get them out of the jar helps keep the mess on your hands down. But generally I do alright with the tiny plastics or spikes, although I keep GULP around, too. GULP can be a very good hang bait on a set rod in a second hole, too, although it is better if jigged.

GULP doesn't work that well for everybody, but a whole lot of folks do very well with some of them. For me there have been some very good successes and some quite dismal failures; it sorta depends on the outing.

One other thing, it can be pretty easily stolen, especially if you get into a sunfish group that is a set of nibblers, and if much of that happens it can get to be expensive.