Best way to reject tens/hundreds of billions of duplicate candidates?

[x34cha]

SQL is no well-suited for this endeavour. Generate the lists and run sort -u on them.

Wouldn't sort -u still give him the ones he has already tried though? Just uniques over two lists. So what you need is to find all passwords in the second list that arnt in the first list and extract those. Im not good with sort/awk/sed etc but I'm sure a quick Google search would do you well.