To open a new bait you need to get the smell out there far and wide.
Something really rank like chickens or some sort of meat fermenting in a sealed 5 gallon bucket for a week or two will gag a maggot. Put it in a burlap bag up high where the bears can't get it, but the smell keeps working.
Buy some cheap bacon and fry it right at the bait site. The smell lasts for weeks. The above items mentioned, like used cooking grease and cattle molasses are always a hit. Bait with whatever you can get large quantities of. This can be difficult, if your bait is a distance away and you have several bears hitting. They can go through a lot of bait if you don't find a way to restrict them.
Later, when bears are hitting, burn some honey. The smell permeates the area well and seems to push them over the edge of wanting to check out the new smell.
I liked using a 30 gallon drum with a small access hole and a hinged top for filling so the bears have to work at getting much out, but it's easy to fill. Just covering the bait with logs and sticks will have you cleaned out in no time.
