Are you saying that the Yiddish word meaning “penis” is properly spelled “shmuck” to distinguish it from the German word meaning “jewelry”?
If so, you might want to edit the Wikipedia entry on Yiddish, which currently doesn’t agree with you.
In re: Yiddish spelling: Yiddish is propoerly written using the Hebrew alphabet anyway, so anytime you see it spelled using English letters, you’re looking at a transliteration in any case. Leo Rosten’s The Joys of Yiddish also lists “schmuck” as an alternate spelling, and there is actually a long discussion of proper transliteration at the front of the book.
(I love that book! Highly recommended for all with an interest in Yiddish, and in Jewish culture in general. It taught me more than my 5 years of Sunday school.)
That happened to me a few weeks ago. I went on a job interview on a Friday morning. At the end of the interview, the supervisor (as with KVS, an African-American) walked me back to the elevator and when it arrived he wished me a good Shabbos.
Zev Steinhardt
Nothing wrong with non-Jews using Yiddish (or Hebrew) words IMO. It is bothersome when they are used incorrectly. Tis amusing to hear Sicilian spoken with a bit of Yiddish peppered in. 
Though I appreciate the concept of editing a community encyclopedia and your informing me about it, I think I will pass. To me Rosten’s The Joys of Yiddish is the authoritative reference book on popular Yiddish still. And in the 1968 edition, “shmuck” is the preferred spelling as it is the one with the actual definations attached.
Re: the “sh” vs. “sch” issue, I like what Rosten says (which is what Eva Luna referred to) “The sch is misleading to the Anglo-Saxon eye and tongue; it may misdirect the innocent into such barbarities as pronouncing shlemiel, if spelled schlemiel, as sklemiel.”
Of course Rosten then “bow[s] to the weight of usage and conform[ity]” when sch usage is wide. I guess that’s another sign of total assimilation, but personally, “sh” is Jewish and “sch” is, to quote Bubbe, goyisher.
My culturally jewish non-practicing friend gives a delighted chuckle if I use a yiddish word. I’ve assumed it doesn’t bother him so I’m glad to see that so far it doesn’t seem to bother folks. (When used correctly.)
These Anglo-Saxons of whom Rosten speaks would do well to note their linguistic heritage. Old English made use of the sc diphthong to represent the disputed sound, without misdirecting the innocent into any barbarous pronunciations. Of course, back then literacy was confined to the upper echelons of society, so any literate person who mispronounced the written sc could hardly be called innocent.
Alas, German represents the sound with the sch diphthong only, misleading English speakers into barbarous mispronunciations of Sommershitze, bisher, or similar words when reading a German text.