Blackstrap molasses: potassium, magnesium, calcium, manganese, copper, zinc, iron. Molasses is derived from sugar cane. Blackstrap is what is left over after the juice has been boiled/cycled a few times and the majority of the sucrose precipitated out. Each cycle leaves the syrup with a more concentrated mineral content (there is also caramelized sugar left over in the molasses). Sugar cane tends to grow an extensive root system; roots can be found growing over ten feet below the topsoil, so sugar cane plants can seek out, acquire and collect nutrients in a way that many others cannot.
Egg shells are primarily calcium carbonate; they have to be pulverized or ground up in order to work effectively. Crushed or pulverized will provide calcium over a longer period of time whereas finely ground/powdered will work faster. On the inside of the eggshell there is also a membrane, which is primarily comprised of collagen (proteins). I suppose it doesn't have to be removed as bacteria will be happy to digest the material, but I would rinse out the inside of the egg anyways.
Of course there are nutrients in fresh vegetative matter, but they are locked up in compounds and are not available to plants (not immediately, anyways). Enzymes and microbes will slowly break the matter (including chlorophyll) down and mineralize the nutrients over time.
Magnesium sulfate (MgSO4) supplies plant available magnesium and sulfur. It is also know as 'epsom salts' and several of the growers here add it to their soil or use it foliarly to treat/prevent Mg deficiencies (sulfur def is very rare when growing in soil). I don't use Epsom salt from the drug store for a couple reasons. Mainly it is because I supply Mg with things like dolomite lime, earthworm castings and molasses; but I also feel less comfortable using stuff on my plants that other folks use to soak their feet in. In other words I would rather use something specifically intended for horticultural use, unless I could be sure of the purity.
Oh yah, and seaweed is good (some more than others) but it should be thoroughly rinsed first. Traces of heavy metals are ubiquitous, not only the ocean.
