By or through

By (preposition)
(via, by means of)
The refrigerator was opened by means of a master key (in what way, by means of which)
Militiamen seized robbers by means of a watchful grandmother (note: not at the expense of grandmother's pension, but with her personal help)

By (not by) means (preposition with a noun)
(within (beyond) one's means)
Banks are not interested in young people living within their means (according to income)
Russia is beyond its strategic ambitions (can not afford)

Most often, you most likely mean “by”;)