This was recieved from Richard of Cambridge:
When cleaning underseal off the subframes (and other body areas), rather than using the labourious method of thinners etc. or the dangerous method of heating it up and scraping it, it is much better to do this:
- Place the subframe on paper
- Get a hammer and some strong flat screwdrivers
- Find a large lump or corner of underseal and place the srewdriver at a shallow angle to the underseal.
- Give the end of the screwdriver a short sharp hit.
This should bring the underseal off in chunks leaving the paintwork below, or in my case it did. Providing that sensible safety precautions are taken this is very easy and safe.
And this is a follow up from Simon Dummett in Leeds:
Richard's method works equally well for removing the bitumen soundproofing stuff inside the car prior to welding (something many people forget - it stinks and ignites quite easily with spot heat...).
Use differing widths of screwdriver head for more difficult areas, narrower heads for the inside edges of the floor ribs and wider ones for the rib tops and troughs, and for the wide, flatter areas such as the footwells or exhaust tunnel, a thin chisel is best.
And another follow up from Carl Houseman in King's Lynn:
Richard's method works a treat as I tried this today and it comes off really well and easily... If you have tar deposits anywhere on the car, a little spot of diesel works wonders also. The Highways Agency actually use red diesel to clean all their tools of road tar.