Im not sure if my dog i just rescued has ear mites or an infection?

She has black compacted wax in her left ear...I have used ear mite medicine about 4 times and the wax around the outer ear has been a lot easier to get out but in the ear c if I look with a flashlight it seems like there is still a lot of buildup. I don't want to stick a q-tip in there because i don't want to push it further down.It smells very foul, What can i use to break it up.I don't really have the money to go to the vet. My dad recommended pouring peroxide in it.any suggestions?