Can we get rid of mold on our own and not use a remediation company?

we manage an apt. building in los angeles. there is mold in one of the units. we don't have pics of her causing it but it is very suspicious that her kitchen sink was clogged at least 6 times in 3 months. professional plumbers were called on few occasions and found nothing wrong but said she needs to stop puttiny stuff in her disposal. the last time we fixed her drainage problem, we found that the pipes were loose! she is a seperate issue, lol. can we remove the mold ourselves as we know what to do or do we have to use a remediation company. we will get a mold test after to verify that the mold has been minimized.