Because the onions pick up chemicals from the paint fumes you cannot eat them after using them to absorb paint.
Onion in room after painting.
Next time you paint add a few drops of clear real vanilla to your paint can to mask fumes.
If i were you i would stop washing the walls because every time the walls become wet the paint dry period is delayed.
Using a mix of burnt umber light red paint in the markings on the fallen onion skin.
Lightly wet the background around the right side of the onion.
Humans can detect aldehydes in concentrations measured in the low parts per billion.
Using the black watercolour pencil darken some parts of a few of the lines.
Use a rigger brush and paint in the fine lines on the skin.
Allow the onions to absorb the paint odors for several hours.
Position the onion halves in the corners of the room.
Then place each piece at the ends of the room.
During the bubonic plague cut onions were placed around homes to keep people from contracting the deadly illness.
After painting a room of your house you might struggle to get rid of the unpleasant fumes.
Remove the onions and throw them in the trash.
So it doesn t take much to stink up a room.
The folk remedy to keep raw onions in the room when you are sick dates back to the 1500s according to the national onion association.
The smell of onions will absorb the foul paint smell without leaving a strong onion smell behind.
In order to keep the toxic smell away use the zero voc paints and avoid the oil based paints and primers as much as possible.
Instead of avoiding painting your home what you need to do is to use the right paint and know the right tricks to remove paint smells after painting a room.
As the huffington post points out you just need to cut up an onion.
After painting a room of your house you might struggle to get rid of the unpleasant fumes.
To actually answer your question the most common trick i could find was to cut an onion in half and place each half cut side up in opposite corners of the room.
After you paint a room the only thing that should linger is how much you love the color scheme you chose.
Neutralize paint fumes with an onion.
Place each onion half in a shallow bowl with the cut side facing upward.
Aldehydes also have a relatively low odor threshold.
After you re done painting cut an onion in half.
If you re not using a brand of low voc paints which tend to only give off a slight smell.
Draw in the fine roots using your black watercolour pencil.