DES random generated bforcing

[pierzi]

Hello

I'd like to ask for best way to crack 6 signs random generated DES hashes (lower/upper alpha) examples below:

Code:

8r7CzL
AXMKD5
AgCdzb
BFQh5A
DHKrTq
EfTq49
Jjpqws
KVyq6Z
LrU4QE
NUZzAt
TEDn5S
VSuZR7

i know that i could use simple mask attack with ?1?1?1?1?1?1 and ?l?d?u settings, also hybrid attack (ex 3 signs dict + 3 signs mask) but this methods aren't to efficient because of checking a lot of unnecessary candidates like aaaaaa aaaaab.... and so on.
Maybe some of You knows better methods to handle with those type of passwords?
Thanks in advance for any information