.htaccess: how to remove Cache-Control’s “max-age”

You need to use the

ExpiresActive On

directive wherever you want to apply Expires headers, for example

<Location / >    
   ExpiresActive On
   ExpiresByType image/png "access plus 7 days"    
   ExpiresByType image/jpg "access plus 7 days"    
   ExpiresByType image/gif "access plus 7 days"

   ExpiresByType text/html "modification plus 5 days"

   <FilesMatch "\.(gif|jpe?g|png)$">        
      Header set Cache-Control "public"    
   </FilesMatch>

   <FilesMatch "\.(html)$">        
      Header set Cache-Control "public"    
   </FilesMatch>

   <FilesMatch "\.(php)$">
      Header set Cache-Control "private"    
   </FilesMatch> 
</Location>

Here's an ideal .htaccess that both compresses and sets sutiable expire headers.

# Insert filter
SetOutputFilter DEFLATE

# Netscape 4.x has some problems...
BrowserMatch ^Mozilla/4 gzip-only-text/html

# Netscape 4.06-4.08 have some more problems
BrowserMatch ^Mozilla/4\.0[678] no-gzip

# MSIE masquerades as Netscape, but it is fine
# BrowserMatch \bMSIE !no-gzip !gzip-only-text/html

# Make sure proxies don't deliver the wrong content
Header append Vary User-Agent env=!dont-vary

<IfModule mod_expires.c>
  ExpiresActive On
  ExpiresDefault "access plus 1 seconds"
  ExpiresByType image/x-icon "access plus 2592000 seconds"
  ExpiresByType image/jpeg "access plus 2592000 seconds"
  ExpiresByType image/png "access plus 2592000 seconds"
  ExpiresByType image/gif "access plus 2592000 seconds"
  ExpiresByType application/x-shockwave-flash "access plus 2592000 seconds"
  ExpiresByType text/css "access plus 604800 seconds"
  ExpiresByType text/javascript "access plus 216000 seconds"
  ExpiresByType application/x-javascript "access plus 216000 seconds"
  ExpiresByType text/html "access plus 600 seconds"
  ExpiresByType application/xhtml+xml "access plus 600 seconds"
</IfModule>

<IfModule mod_headers.c>
  <FilesMatch "\\.(ico|jpe?g|png|gif|swf)$">
    Header set Cache-Control "max-age=2592000, public"
  </FilesMatch>
  <FilesMatch "\\.(css)$">
    Header set Cache-Control "max-age=604800, public"
  </FilesMatch>
  <FilesMatch "\\.(js)$">
    Header set Cache-Control "max-age=216000, private"
  </FilesMatch>
  <FilesMatch "\\.(x?html?|php)$">
    Header set Cache-Control "max-age=600, private, must-revalidate"
  </FilesMatch>
</IfModule>

<IfModule mod_headers.c>
  Header unset ETag
</IfModule>
FileETag None

<IfModule mod_headers.c>
  Header unset Last-Modified
</IfModule>

The following article covers what it does and also talks about compression:

http://www.samaxes.com/2009/01/06/more-on-compressing-and-caching-your-site-with-htaccess/

Hope that helps.