I have been toying with various baits a lot recently, here are a few that have or have not really worked so well...
Sweetcorn, ok for smaller carp, fed 2 pieces on a sz 12 hook seems to be producing a lot of 1 - 3lb'rs
Bread has not been good round my area of late, getting pecked to bits by smaller fish before large carp have had chance to get to it.
I have been making pellet style baits out of luncheon meat or potato as well.
Using a piece of 15 mm copper tube makes good selective size pellets of either.
Try really spicing the luncheon meat up with a good dose of paprika, chili and all spice powder, leave for a couple of days before use so the spices have plenty of chance to soak into meat.
Same for spuds, cut some 15 mm pellets again and soak for a few days in coffee, oxo and various spices.
Finally, a bait that has been working very well, take a trip to Lidl and get some of their mini salamis, spiced or smoked. cut into 1 inch long pieces us off cuts to add a pva bag full on cast...
A very tough long lasting hook bait that will put up with carp knocking it about, you can try taking a few pieces and again adding a few extras to them.