Over the next two weeks, REROC will be staging chemical collections for household quantities of poisons, toxins and batteries of all sizes.

"Mostly, it's old batteries, smoke detectors, gas bottles and unused paints," said REROC executive officer Julie Briggs.

"Every now and then though, someone comes in with some really nasty toxic waste, you know, if you have half a bottle of strychnine, and heavy pesticides you haven't used."

Subsidised by the NSW Environmental Protection Authority, collections are run in the Riverina every two years.

Chemicals can be taken to Gregadoo Waste Management between 9am and 3pm on May 18 or May 25.

"If you've been hanging onto these things and you haven't been sure what to do with them, then this is the time to get rid of them for free," Ms Briggs said.

"[Otherwise] you'd have to go to arrange a special pick up that will cost you. You have to take them to a special collection service, and there are no local ones."

Several years ago, one of the EPA officers began keeping a 'show and tell cabinet' of the weirdest and worst chemicals that have been deposited during a weekend collection.

"He had some chemicals you wouldn't even know any more. The package hadn't been seen for 40 years, these are poisons that were used once then placed on a shelf to sit there for decades."

While local collections can happen so infrequently, Ms Briggs affirmed the paramount importance of storing unwanted chemicals safely in the interim.

"These are chemicals that need to be respected," she said.

"If it goes into landfill, it can begin to leech and go straight into our waterways. [Or] it could be accidentally touched by someone.

"If it's leaking, you have to pick it up using protective gloves and put it in another sealed container, a metal buck or something, to keep the leak contained."