In , CyberTaz told
us an interesting story. My reply to this story is at the bottom of
this message.

Hi Spike-

Wingdings, Webdings, Symbol, etc. are fonts created just like Times
New Roman, Arial and the rest. Where you are "going wrong" is that
fonts are vector shapes designed based on lines & curves defined by
formulas which you cannot directly modify without the appropriate
design software. The way you are trying to modify the one 'instance'
of the character causes it to be converted to a rasterized image made
up of square pixels which results in the jaggies.

To add to this:
You could try to find font editing software (I think there are some
very basic font tools somewhere deep in the Coreldraw suite, but I'm
not sure) and export the glyph you want to clip art. Then you can edit
it as much as you like.

--
Amedee Van Gasse