At the weekend I started to clean up the floor pan of under seal. I used a propane torch to heat up the under seal and scrape off the seal then cleaned up the rest of the mess with a good dose of thinners.

This is what the panel looked like before cleaning most of the seal was already removed except in the hard to reach places as you cn see on the inside chassis rail.

These show the panel cleaned up before I repair the rust that I found. In one of the pics i tried to show the pinhole rust spot which I may well have missed had I sent the car off to be soda/sand blasted. this method may be time consuming but in finding spots like this I think worthwhile.