def remove_items(lst, items):
    items = set(items) # unnecessary in your case
    pos = 0
    for x in lst:
        if x not in items:
           lst[pos] = x
           pos += 1
    del lst[pos:]

a=[2,6,79,10]
b=[6,7,2,0,8,5]

common = set(a).intersection(b)
remove_items(a, common)
remove_items(b, common)
print(a)
print(b)

assert a == [79,10]
assert b == [7,0,8,5]