Blue painted revellers at Carriacou carnival.

Carnival paint on Carriacou.

Grenada and the Grenadines - admin.

Where in many countries people dress up in beautifull costumes during carnival, in the Caribbean these habits are distinct.
Most islands have their own traditional figures like sailors or dames, and the use of paint and engine oil is widespread.

The reason is simple.
In the past when the colonialists had their pretty costumes, the labourers had to do with what was at hand.

Not to mention the convenience of splashing on paint or oil.
The cleaning afterwards is another story.
On Carriacou many go to the beach afterwards, to wash the paint away in the sea.