''After careful consideration it is believed it would not be in the public interest to continue with the prosecution.''
He said Marsh, 36, had ''admitted her guilt to this charge'' by accepting ''a simple caution''.
The court heard that the former singer, who did not attend the hearing, had also paid prosecution costs which included the costs of clean-up and investigation.
Mr Scott added: ''It is unlikely the offence will be repeated.''
Chairman of the bench Chris Hampson withdrew the charges against the defendant.
Officials launched an investigation after a pile of rubbish was abandoned by a roadside, the Manchester Evening News reported.
It included building rubble and pieces of furniture - plus some old scripts which were traced back to the actress.
A spokeswoman for the mother of three told the newspaper she fell victim to a conman who offered to dispose of the rubbish from her home during renovation work.
Marsh, who is engaged to ex-Hollyoaks star Jamie Lomas, 32, was said to be ''horrified'' to learn of the prosecution.
She claims that a man dressed in a yellow high-visibility jacket knocked on her door and offered to remove the rubbish - so she paid him £60 and forgot all about it, the MEN reported.
Gena Merrett, Salford City Council assistant mayor for environment, said: ''Our enforcement and prosecution policy requires us to constantly review cases in light of new evidence and information.
''After careful consideration of the facts, it is believed that it would not be in the public interest to continue with a prosecution.
''Ms Marsh has admitted her guilt to this charge by accepting a simple caution and has demonstrated her regret by paying all costs incurred by the council both in terms of the clean up and carrying out the investigation.''
A Coronation Street spokesman said: "Kym's relieved the prosecution has been withdrawn and she's now able to draw a line under this matter.
"Kym paid someone in good faith to remove the rubbish but realises now she should have asked to see a licence.
"Kym was horrified to discover her rubbish had been illegally dumped and has offered to pay for the cost of the clean-up that resulted."