Thousands of laughing gas canisters that litter Cardiff may be saved from landfill in a new recycling scheme.
The canisters of nitrous oxide, also known as nos, were among rubbish in Cardiff Bay after crowds gathered by the Senedd despite Covid restrictions.
Cardiff Rivers Group (CRG) now aims to recycle the metal tubes, after collecting "a couple of thousand".
It is illegal to sell it for recreational use like this, but it is legitimately used in catering, for the likes of whipped cream, and for medicinal use.
CRG chairman Dave King said of the canisters, "we are finding them all the time", and in recent weeks volunteers had collected thousands.
Up to now though, the metal canisters have either been incinerated or sent to the landfill, and volunteers have been trying to find a way of recycling them for months.
Now the litter pickers are hoping to collect as many of the canisters as they can, which can block drains, and recycle them at a scrap metal company.
Mr King said volunteers had collected hundreds of the canisters in the last three-to-four weeks, from parks and streets across the city.
"We did a litter pick in Butetown just after the last lockdown and picked up over 700 in one session," he said, adding a couple of hundreds more had been found in Hamadryad Park recently.
"We've seen how many have been left in the Bay in recent nights...we are finding them on an industrial scale."
Mr King said the group had already collected around 60kgs (132lbs) of the cannisters, and would keep them in a shipping container until they had about 300kgs (661lbs).
They would then take them to European Metal Recycling to get them recycled, and use the cash to help fund their clean-ups and donate to other charities in the city.
"It won't take long," he said, adding the group were hoping to set up drop off points in the city for people to recycle cannisters they found.
"We have wanted to recycle the canisters for a long time simply because they are made from steel and are readily recyclable," he added.
"The stumbling block has been the worry that some may still have the gas in them when they go for crushing at the scrap yards."
Jemma Bere, from Keep Wales Tidy, said the number of the canisters being collected in the city was "staggering".
"Sadly, anecdotal evidence suggests it is a similar picture across many parts of Wales," she said.
"Like all litter types, discarded canisters and balloons aren't just unsightly, they pose a real threat to wildlife and the wider environment."
Nitrous oxide - the highs and lows
- Effects include euphoria, calmness, dizziness, difficulty thinking straight, giggling and hallucinations
- Inhaling nitrous oxide from the canister or in an enclosed space - like with a bag over your head - is very dangerous
- By inhaling nitrous oxide the user risks falling unconscious or suffocating from lack of oxygen. People have died this way
- If someone collapses after using nitrous oxide, turn them on to their side, call 999 and stay with them until an ambulance arrives