I have steel 95's, steel 3L, Alum 80's, Alum 6cf, Alum 40's, Alum 30's, Steel 72 all in my garage some for over 20yrs in unheated garage in Minnesota never a problem. Most stored full in the case of the 95's at 3200psi
Just took 13 in for hydro's all passed.
Al