Cleaning Porous Ceramic Tile

Any ideas on how to clean porous ceramic tile? It has never been sealed since it was installed 4 years ago. Thanks!
Please remove NOSPAM from email address when replying.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

what kind of tile is it?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.