What is the weird cloth in my army surplus pocket?

[Thomas Peterson]

I just bought an assault vest that is UK army surplus and in a pocket there was a long rectangular piece of sand coloured cloth.

Is it a head wrap or something for desert wear?

 

[Jerry T]

a cleaning cloth for getting smudge marks off your night sight lenses

 

[Katie]

diaper rash

 

[Mr Puma]

With it being British, who knows?