solar – Proper torque specs and cleaning busbar and lug connections – GWC Mag

I have 4 stud M8 (5/16”) Bus bars which connects 4/0 and 3/0 copper lugs from the LiFePo4 batteries (2 5KwH) and Inverters 2 6 Kw split phase off-grid).

I wanted to know what can I use to clean the contact area with properly. Is 99% isopropyl alcohol sufficient?

Also, what should be the torque spec for the 4/0 and 3/0 lugs using an M8 nut.