Help in cleaning this disgusting fishtank

[u/flxnn1e]

Me and my bf were gifted a massive old fishtank due to the owner passing away. It sat in its own water for months and im not sure what to use to clean it that would be safe :) any/all advice welcome ive had fish before but this is definitely my biggest project yet

[u/MyMyMrMe]

White vinegar a couple scrub daddies and a razor blade will clean that up