Maybe make the jars have a roll at the rare / very rare drop tables of their originated boss?
Jar of Swamp --> pet snakeling, serp vissy, magic fang, mutagens, tanzanite fang
Jar of Dirt --> Pet Kraken, Kraken Tentacle, Trident of the Seas
Jar of Sand --> Dragon chainbody, Dragon 2h, Kalphite Princess, Kalphite Head
Jar of Souls --> Primordial/Pegasian/Eternal Crystals, Smouldering stone, Hellpuppy
Jar of Miasma --> Bludgeon (complete) Abyssal whip, Abyssal Dagger, Abyssal Orphan
Jar of Darkness --> Skotos. Dark Claw, Uncut Onyx
Jar of Stone --> Noon, Granite ring, Gloves, Hammer, Tourmaline core
