He joined organisers of the Zero Waste Scotland campaign on the streets to do some litter picking and tidying up.
Mr Alexander said: "It was great to join the volunteers out in Paisley town centre collecting litter.
"We all want to live in a clean and tidy town and keeping our streets free from litter is important.
"As well as being a real eyesore, litter can cause problems for wildlife and if it's on the roads can also be dangerous.
"It also costs council taxpayers money to clean litter from the streets, which is why it is important to raise awareness of the problem."
The Litter Week of Action ran from August 19 to 25.
It aimed to raise awareness of the litter problem and encourage people to bin their rubbish or take it home.