I need an Excel genius!!

I have a bunch of text strings in an Excel file (2008 for Mac) that look like this:

Milwaukee
New York
San Diego 1234
XYZXYZ San Juan
Adelaide XY Australia
Boston ABC123
AlbanyXYZ

And I want it to look like this:

Milwaukee
New York
San Diego
San Juan
Adelaide Australia
Boston
Albany

That is, I want to remove 3 things:
1. Numbers
2. Extra leading/trailing spaces
3. Capitalized letters that are immediately next to other capitalized letters

I took care of 1 and 2 with =TRIM(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(A1,"1",""),"2",""),"3",""),"4",""),"5",""),"6",""),"7",""),"8",""),"9",""),"0","")), but how do I take of 3?

How can I remove only those capitalized letters that are right next to other capitalized letters?

Thanks for your help!!