Cleaning floor times

Just wondered if anyone had any tips for cleaning old floor tiles? Is there a machine that can be hired for such jobs?We are having a new kitchen but are keeping the original floor tiles. They look quite dirty in places. Any ideas? They are small squares with little mosaque bits in the pattern. We'd also like to varnish them to give them a gloss finish..

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload 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.