Best way to get Plutonium/Toxic Sludge in late game

[UF7_YO]

Hey! I've looked around for tips on how to get the most plutonium and sludge and it seems to be to spawn lots of skeletons around lighthouses and kill them with the nuclear sword. It seems to work for other people and one video seems to show thousands of plutonium spawning in just a few kills. However, I'm still getting the same amount of plutonium with or without the lighthouses. The lighthouses are increasing the number of bones and great skulls though.

Is there a better way I could be doing this? I have all lands and tools unlocked.

[NOIRE-]

the fastest way (and the hardest one) to get toxic sludge is to constantly kill toxic boss (from toxic sigil)

before you get strong enough to do that, void biome is your only choice.
you can also get it from killing monster with nuclear sword/bow, work best with upgraded necro rod, but the problem is mid-late game generally you will have dozens/hundred of droids and you need to slain the monster with the nuclear wpn yourself.

[NOIRE-]

Now if only necro rods has way longer range, i could just trapped the skeletons in 3x3 area and kill them with nuclear bow from afar.