A party goer was fined for being drunk and disorderly at an illegal rave attended by up to 40 people on Sunday night.
A 30-year-old man from Croydon was arrested by police officers at the scene and taken to a south London police station.
He was later given a fixed penalty notice for being drunk and disorderly.
Police took more than four hours to disperse the crowd, some of whom were dancing and causing trouble until the early hours of Monday morning.
There were also reports of a number of minor disturbances in the area with men kicking bins, a bottle being thrown at police and a bus stop being damaged near the party in the Seven Islands Pond area of the common which began on Sunday, April 6.
Mitcham Common Conservators member, Councillor Martin Whelton said the gathering was totally unacceptable.
Coun Whelton said: "It caused a lot of distress to residents and left a lot of rubbish behind.
"What they did was completely and utterly unacceptable."
Power generators were being used to blast out tunes until at least 3.30am when the gathering was dispersed by police.
Rubbish including empty Courvoisier and Champagne bottles were seen to be left behind, as well as an empty marquee and plastic buckets.
Officers were called at 10.45pm on Sunday.