How to remove malware from my Mac?

I have a iMac (2013) running on the latest update anyways I had malware and adware for years now without knowing so weeks ago I decide to download malwarebytes it ran a scan and says everything is fine but I take a closer look to see what it was scanning which was PUP, OSX.wirelurker,OSX.Backdoor,Adware.Ironcore and much more but It only detected one malware/adware but weird part is no malware or adware had ever pop in my screen or locked me out but I'm scared now to reboot so what do I do now? If one of the biggest anti virus company can't detect it.