Whats the best way to remove hamerite paint?
Its been on for about six months.

paint stripper!

Sand blaster (for those with a compressor)? Hope the Ebay type tube suction types work- just bought one!!!!

Angry grinder with a wire brush?

'The Tool' will do it but wear your chain mail overalls

I usually start with nitromors, not around aluminium though, as its caustic.

what material is it painted on? and do you care about the primer or other layers below?

So depending on the answers to the above, it can be checmical e.g. paint stripper or mechanical e.g. sanding and its variants.