The Half Dollar shell makes a clunk instead of a clink and looks too shiny. Is this normal?

Yes, the gaff usually doesn't sound like a real coin. And if it's for Scotch and Soda, why does it matter if it's too shiny? It's not being compared to another silver coin.

Carry the coins in your pocket for a while. This will dull them, just be careful not to spend the coin.

I drop coins from one hand to the other by dropping the first coin (with the shell down) first. There is still a difference, but it is slight.

If you are counting several coins into the other hand a little jingle of the coins alrady there can mask the difference. I often just Disengage and toss the actual coin while palming the shell -- depends on the routine. I think you only have to do the 'clink' occasionally anyway to establish a Pattern of Performance. The actual pouring of several coins from hand to hand doesn't make a 'clink'

Ok so it is something to be expected. Ok. Thanks guys! It was just a little weird because the heads side of the shell was like tin foil but the insert looked regular when in. Only one person noticed so far but he shrugged it off. Thanks guys!

If you have a fireplace - ashes can be used to dull the coins so nicely. I have a set that I polished and then decided I wanted to dull down a bit and took some of the chunks of charred wood (burnt through but still chunky) and used that to polish the coins down a few grades in dullness. Also, it tones the coins nicely by filling in the cracks with dark charcoal. Damp cloth to wipe off the black powder and all set. Just one more option besides the bleaching method.
Michael

One more tip - a teflon insert in the shell will deaden the sound tremendously. It dampens the clinky sound. It will still sound tinnier than a solid coin but having them jiggle in your hand wont tip the gaff anymore.