Berlin (CNN) Irmela Schramm has the eyes of a hawk. Mid-stride, the 70-year-old suddenly yells "Halt!" and points at a metal container across the street in Berlin's Lichtenberg neighborhood.

It's hard to make out the graffiti amid all the other spray paint but after some squinting, the words jump out: "Nazi Kiez" or "Nazi neighborhood." And scrawled on a small electrical box next to it: the unmistakable lines of a swastika.

Schramm quickly rummages through her bag and whips out a can of red spray paint. Then she gets to work before stepping back to survey the result. A giant red heart now blocks any view of the swastika.

"A beautiful heart!" she exclaims, waving her stained fingers in delight.

Irmela Schramm has spent the best part of the last thirty years defacing or removing racist graffiti from Berlin walls.

Schramm is on a mission to rid the world of neo-Nazi and racist graffiti, one spray-painted heart at a time. She calls herself a "Polit-Putze" -- a political cleaner. Her tools: a can of red spray paint, nail polish remover and a scraper that she carries in a cloth bag with the hand-painted words "Anti-Nazi."

"I'm really concerned by this hate propaganda. And I want to take a stand," she tells CNN. "Not just hollow words. But to do something. I could look at that swastika and "Nazi Kiez" graffiti and say 'oh, that's awful' and walk by. But no one would dare to do anything. Well, I don't want to wait for someone else to do something about it."

Scrubbing away hate

It started more than 30 years ago when she saw a flyer supporting convicted Nazi war criminal Rudolf Hess plastered to her neighborhood bus stop. It was still there when she returned from work. Disgusted, she took out her house keys and scratched it off.

"I just scrubbed the hate away until it was all gone," she says with a smile, "It was a fantastic feeling afterwards. This mind pollution was gone!"

Schramm says she has removed more than 130,000 signs or stickers from German walls over the last three decades.

Since then, Schramm has developed a kind of sixth sense for where neo-Nazi material may be lurking. Train stations are a favorite hunting ground. So are supermarket parking lots and playgrounds.

She has traveled across Germany and six other countries on this quest, and can spend up to 17 hours on the "hunt" a few days each week. She estimates that, over the years, she has removed or painted over more than 130,000 signs and stickers.

Changing attitudes

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Germany's Institute of Human Rights has cataloged more than 10,000 hate crimes in 2015, a jump of 77% from the previous year. Far-right groups have capitalized on public fear and suspicion of refugees and migrants, in particular, after Germany accepted more than 890,000 asylum seekers last year.

Schramm says she can see that change on the streets. Anti-refugee stickers especially, she says, are easy to slap on to any street sign anonymously.

"The threshold on the misuse of freedom of speech has deteriorated over the last few years. I think it has now reached rock bottom," she says. "People tell me I am intolerant, that I don't respect the far-right's freedom of speech. But I say: Freedom of speech has limits. It ends where hatred and contempt for humanity begins."

Throughout the years Schramm has kept a scrapbook of neo-Nazi stickers and graffiti she's has come across.

'Schramm, we're coming to get you'

At home, Schramm shows us her catalog of neo-Nazi graffiti, including a 1989 photo of a young man blocking her path and giving her a Nazi salute. The language may have changed but the message remains the same.

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In the 80s, crude caricatures of Jews and Africans coupled with Nazi slogans to "remove" them. From the 90s, she has photos of "Turks out!" scrawled across train station walls coupled with swastikas.

Today, she says, she finds anti-Muslim graffiti along with coded neo-Nazi rhetoric. She shows us a photo of a graffitied number "88" which stands for "HH" or "Heil Hitler" -- H being the 8th letter in the alphabet.

Her relentless drive has landed her on a "most-wanted" list of a neo-Nazi group and she has received plenty of violent threats. She's even come across a large graffiti sign that read "Schramm, we're coming to get you."

Police have told Schramm not to provoke attacks with her mission and are often bemused by this 70-year-old woman brandishing a can of spray paint. Usually, she's let off with a gentle warning but for the first time in October, she was threatened with a €1,800 euro fine (around $1,875) for defacing public property if she continues her unconventional hobby.

Facing the populist wave head-on

In the East German town of Bautzen -- the scene of repeated brawls between refugees and residents -- she found graffiti that read: "Democracy = Death to the People."

Once Schramm got her hands on it, the text became "Democracy Loves the People." But when an off-duty police officer caught her in the act, he threatened to put her in jail overnight.

"I told him: Go ahead," she laughs, "I need the holiday!"

She acknowledges that with Germany's far-right movement growing alongside suspicion of refugees, she may never see an end to her war on neo-Nazi and racist graffiti. But she has no plans to slow down.

"I've just always felt: If you don't do it yourself, it just won't get done."