Whizzing
What is it?
How does it work?
On the PCGS website, Rick Montgomery (then of PCGS) offered the following definition of Whizzing:

"...In its simplest form, whizzing a coin is done by attaching a wire brush to the end of an electric screwdriver and using the high revolutions to  move the metal on the coin's surface.   More sophisticated whizzing involves putting artificial luster on the coin after the initial wire brushing is completed."
(my emphasis)

Disregarding the obvious erroneous assumption that an "electric screwdriver" is capable of high revolutions, what did Mr Montgomery mean when he said: "...move the metal on the coin's surface"?
On another page he adds: "...surface metal is moved mechanically to create the illusion of luster."

Now wait just a minute there. "Move metal", with a wire brush?

Plastic deformation of metal with a bit of fine flexible wire? Melting of the surface by friction with a spinning brush? There's something screwy going on here. A wire brush works by abrading the surface of the metal being polished. The only "movement of metal" involved is microscopic - and is mainly the "movement" of metal from the surface to the benchtop, in the form of filings (or "grindings").

Is this pronouncement of Montgomery's a function of of lousy editing - deficient proofreading, a substandard understanding of metalworking techniques, bad choice of expression, or [D]; all of the above?
before - click to enlarge
before		 Well, let's find out what effect this nasty process has on coins, and the means by which it does it.

WARNING Sensitive numismatists should now click on the [BACK] button.

At left we have the brave volunteer for this experiment, a 1943 Australian florin in VF condition.

Aim: to investigate the mechanism and effect of "whizzing".

Method:

  • obtain a suitable silver coin, VF or better, lacking lustre,
  • whiz that coin, using a variety of
    • brushes, and
    • methods,
  • examine and photograph said coin, microscopically, and
  • report results.
Results: are presented in the table below. 		after - click to enlarge
after
Here is a series of 18 pairs of thumbnails (such as at left). Each pair features a "before" and an "after" photo or photomicrograph of the brave martyred florin. The thumbnails link to large jpgs (typically >100kB).
Similiar to the above option this this page features half a dozen pairs of "before" and "after" photomicrographs, displayed side-by-side on the same page. By necessity, these images are smaller then the ones above, but they are perhaps easier to compare.
The choice of the brushes used had a huge effect on the results. Here is a brief rundown on the three types tried.

You really should read this before examining the coin photos too closely, because it explains quite a bit of the results obtained.

This page will be interesting if you're interested in the photo techniques and equipment used here.

If you're not, it won't be.

Just for a bit of extra fun, I took a modern coin (from an indeterminate country which doesn't have anti-coin defacing legislation) and tried some really heavy whizzing. I still can't get that danged metal to move!
Conclusions: Its always a bit suss when your conclusions match your preconceived notions, but, well...

Its like this... I learnt some things about whizzing (not what I expected) but I was not able to disprove the metal moving notion. (Ever tried to disprove a transient phenomenon? Like ghosts?). I certainly found nothing to support it, and I did find some effects which provide palpable arguments against the contention.

Anyway, a summary - such as it is - of my conclusions may be found here.

Recommendations:
  1. Don't! (whiz, that is)
  2. Don't believe everything you read - especially on websites.

Email: brickbats or bouquets.
Usenet: Ping "A.Gent" on rec.collecting.coins.