Not really sure of a good way to do that. DId a google search, but didn't come up with much except for posts where people tried it, but nothing really 'stuck'...i.e. whatever they tried to plug it with eventually came loose.

I was almost thinking I could put a tiny spot weld on the end and then grind it flat...but that's maybe a little cheesy and a lot of work when you realize that you have to do it 16 times and if you screw up, you have to buy a new pushhrod anyways...