Question

What alternative methods can be used to eliminate cockroaches if bombs are ineffective?

Answer 1

use insecticides. if that wont work, just kill them manually (by stepping on them)

Answer 2

if you live in an apartment complex, there is no getting rid of them. they just spread from everyone else's apartments to yours. if you don't live in an apartment, then keep doing the bombing. it might sound harsh, but you just have to keep bombing plus keep the poison out for them to eat. cockroaches are very resilient, just keep at them.