Wow good catch! That could've been catastrophic bringing those toxic axles indoors. Next time you should wear gloves, I hope you at least had an N95 mask on. If you haven't already, you should consider getting your nickel plating shot and booster.
I can't believe you just threw them in the trash like that. Don't they have hazardous waste facilities where you live? C'mon, man, be part of the solution.
I don't own a battery drill. Will it make any difference if I gently tap the wheels with a sledgehammer first before removing the axles delicately with an angle grinder?