He sure didn't do anything with them.
Yeah he did, he used his genius IQ to rip off Arthur Jones HIT ideas and call it Heavy Duty.
It's amazing the cult-like following Mike has. Padilla, Coe, Calendar, Robinson, Zane, Bannout all have there fans, but not the obsession of Mentzer fans. Even uniquely popular guys like Platz or even Ferrigno who are both really well known bodybuilders don't have psycho fans like Mike.
When you stop and think about it the biggest for Mike's popularity IS losing to Arnold (and throwing a tantrum) otherwise he wouldn't have the enduring popularity that he does.