Accusing men of “gender aggression”, 20-year-old Anna Dovgalyuk claims her native Russia is slow to counter the problem.
Men sitting with their legs spread wide on public transport are guilty of “a disgusting act that is being fought around the world – but hushed up here”, she said.
Ms Dovgalyuk, who studies law, went into battle against manspreading in the St Petersburg metro underground train system splashing a mix of 30 litres of water and six litres of bleach into the groin areas of men she deemed to be sitting in an offensive manner.
“This solution is 30 times more concentrated than the mixture used by housewives when doing the laundry,” she warns targets in a video.
“It eats colours in the fabric in a matter of minutes leaving indelible stains.”
She added people can now tell who the manspreading culprits are due to their “identification spots”.
“So, everyone can immediately understand which body part controls the behaviour of these men,” Ms Dovgalyuk said.
She claimed her video was dedicated “to all ‘men’ for whom manspreading is the norm of conduct” and to be acting “on behalf of everyone who has to endure the manifestations of you declaring your macho qualities on public transportation”.
Calling herself a “social activist”, Ms Dovgalyuk has previously achieved worldwide attention by flashing her underwear to commuters to raise awareness for up skirting laws in Russia.
Critics asked how she was helping counter the menace of up skirting by flashing her undies.
“I am a social activist who advocates for women’s rights and against discrimination in any form,” she said.
However, Russian news outlet Rosbalt claims her video was a sham and that she had used actors.
But the campaigning student denies this.
“My action is absolutely real,” she said.
She added that no commuters had sued her so far.
“I don’t think people are going to go to the police to file a report about jeans,” she said.