The man, who goes by the name of 'Nick' on Twitter and lives in Louisiana, shared the gross photos on his page and they have quickly gone viral.
The image shows a metal tray that he claims came out of one of the chain's ice cream machines - and it appears to be full of green gunk.
Posting the snap to Twitter on July 14, he wrote: 'This came out of McDonald's ice cream machine in case y'all were wondering...'.
His tweet has since had 14,000 retweets and thousands of comments.
He then added another tweet, writing: 'People keep quoting this and saying this is the reason it's always down when it works perfectly fine with this in it.'