At least 40 councils have stopped levying the charge, saving the sector an estimated £120,000 a year, after Labour MP for Southampton Alan Whitehead wrote to all 376 waste collection authorities on behalf of the association last February.
Whitehead's letter told the authorities that charity shops can be exempted under the Controlled Waste Regulations 1992. The legislation allows authorities the discretion not to charge charity shops to dispose of waste, but most charge anyway.
The association estimates that charity shops under the jurisdiction of local authorities that continue to charge them are landed with an average bill of £400 a year to have other people's rubbish taken away.
Unsuitable items left outside charity shops that cannot be sold on for rag include heavily soiled or torn clothing and broken electrical appliances.
Despite the success of the campaign, at least 49 local authorities are continuing to charge for waste disposal, although some have decided to review their policies.
"Our campaign continues," said David Moir, head of policy and public affairs at the association. "This year we will put pressure on larger authorities, particularly those with large numbers of shops.
"Some argue that charity shops are commercial operations because they are on the high street. Others argue that a judgement from 1975 concluded that charity shops did not serve a charitable purpose so should not be exempt, but that ruling was overturned by the Local Authority Finance Act 1985."