Don't forget all the service vehicles that were fine for continued use until they later became so lethal they had to be entombed: which included £347,000 worth of police cars...

https://www.independent.co.uk/news/uk/home-news/salisbury-attack-novichok-poisoning-amesbury-wiltshire-russia-emergency-vehicles-buried-a8518126.html


Then there was the checked out & uncontaminated cat that lived on in the Skripal house until they starved in to death...

oh and the roof...They finally went back and took the whole roof off...and entombed it too.

https://www.nytimes.com/2019/03/01/world/europe/novichok-salisbury-skripal-attack-house.html

-With nearly 200 military bods in hazardous materials suits on the job, I reckon this was the most expensive case of removing a complete lack of evidence the world has ever seen.