metal, medal, meddle, mettle

Metal or metal means one of the substances mined to use in making goods and machines--
Steel, iron, aluminum, lead, tin, brass, copper, gold, silver and platinum are all types of metal.
Some things made of metal can rust. That's why they are painted.

Medal or medal means an emblem or medallion  ( looks like a coin )  made as  an award or to commemorate a special event--
He won a gold medal in the swimming competition.
He was awarded a medal for bravery.

Meddle or meddle means to interfere where one is not wanted--
I wish she wouldn't meddle in my affairs!
They seem to like each other, but let's not meddle.

 Mettle or mettle means temperament  or  spirit--
"When a man's an empty kettle, he should be on his mettle..."
The battle was a test of the mettle of those involved.

Now that you know that, you can say--
"A witness decided to meddle, and after reporting the display of mettle, the hero was awarded a medal made of  shiny silver metal."

Note--a "medalist" is someone who has won a medal.
A "metallurgist" is someone who studies metal.

Note # 2--"meddlesome" describes a person who often interferes or meddles--
What a meddlesome old woman!
"Mettlesome" means brave or spirited--
Their leader, a mettlesome fellow,  inspired confidence in his troops.