Schools spend £39m a year clearing up rubbish and repairing damage caused by vandals, an environmental group says.
Eco-Schools is also warning that much of the £100m spent on electricity and £106m on water is going to waste.
England's schools are facing a budget shortfall of around £500m, with some up to £500,000 in the red.
Using more energy-efficient lightbulbs and removing old boilers would reduce costs, stopping the "haemorrhaging" of millions of pounds, Eco-Schools said.
Flush controllers
The group's chief executive, Alan Woods, said: "These aren't major changes and, while they involve a little outlay, the pay off is smaller bills in the long run."
He also recommended setting up recycling facilities for cans at schools and fitting flush controllers in toilets.
The watering of school gardens should be restricted to once a week, while children schould receive more information on the environmental damage caused by litter, Mr Woods added.
Eco-Schools found £158m was spent on paper and stationery each year.
Mr Woods added: "It may sound simplistic, but if every school in Britain fitted energy saving light-bulbs, they'd save £10 per bulb in costs each year.
"By tuning their old boiler, they'd also use 40% less fuel and could cut water costs by replacing worn washers on taps."