Punctuation for Dummy's: When to Use an Apostrophy?

Are you confused where to put an apostrophy, or maybe apostrophe? Here's a poem to help you remember, or just some confusing, bad advice, filled with misspellings and apostrophe abuse. When should an apostrophe be used? Do you use an apostrophe in a plural or in a pluralized abbreviation? This poem doesn't tell you when, it asks why?

Do you use an apostrophe when pluralizing a date correctly? Is it in the 1960s (plural) or 1960's clothing (1960 possessive) or 1960s' clothing (1960-1969 plural possessive)? A humorous poem filled with typographical errors and other nonsense, as in Dummy's for dummies. A dummy's guide to punctuation for dummies:

Plural's possessives,
extra added to Ss,
where did that apostrophy go?
Pages and pages of typeo, tpyo, or typo...
before after an o?
Its punctual elation
overused in erroneous abbreviations,
and trophys vacation's
(no awards if you notice
but perhaps less pleasing to read).
If your filled with greed
copyright apostrophies',
inserted between s and a zero?

like all of my poems and articles on AC,
Copyright: needle felted dogs