Cleaning glass decanters

My crystal wine decanters
Had gone dullish over time.
A wash in soapy water
Never could remove the grime.

Inside, a sort of whitish film
Was all that could be seen.
I tried all kinds of methods,
In a quest for sparkling clean.

I bought some strange ball bearings.
With some water these are shaken.
They are said to scour the debris,
But that claim is much mistaken.

A foam had proved successful,
On those bath tub soap/lime rings.
Sprayed on, it doesn't run straight down
But dutifully clings.

"If it works," thought I, "on scummy stuff,
Those products of ablution,
Then it ought to be quite good on glass."
It wasn't the solution...

In I squirted it. It frothed straight out.
Did not remove the tarnish.
But the wretched stuff went everywhere,
And stripped my nails of varnish.

I looked on-line for methods
That would make my glass less drab.
And one idea had some appeal -
A denture cleaning tab.

Three Steradents I duly crushed,
(When whole, they didn't fit.)
Would the end result be worth it?
No, they didn't help one bit.

So I reached for Flash - a liquid.
It is green and not that thick.
And, swirled round the inner surface,
This product did the trick!