Wow 10kg is a lot. I had a similar exercise when I moved into my house and my parents took the opportunity to dump all my childhood stuff on me to get it out of their place. I didn't have quite that much lego but still a fair bit. Sorting out by colour first worked well for me because I had a few quite distinct sets.

[–] Dave 3 points 1 year ago

This lego was picked through by resellers so had lots of partial sets and no instruction books. It sounds like a lot but the box it came in wasn't all that big. I'd say smaller than a 50cm cube.

I haven't sorted by colour because I wanted to get the different shapes for building things and I knew I wouldn't have enough containers for splitting by shape as well as colour, I've over time worked out which pieces are common and pulled those out, with more unique pieces left to be sorted along with some pre-assebled stuff I don't want to disassemble before identifying the set. There ae still heaps of tiny pieces to sort through too.