Ask A Scientist General Science Archive

name         Joanne M.
status       other
age          60s

Question -   What degree in Fahrenheit is reached before a stain in
clothing can no longer be removed?   In other words, we wash the article
in cold water and may even be able to add some warm water until some
point (degrees of Fahrenheit) when the blood will become
"set....."
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There is no fixed temperature for "setting" a stain. It depends upon the
fabric, the chemical doing the "staining". how old the stain is (older is
more difficult usually). The presence / absence of detergent and other
laundry products are also a factor.
Since you mentioned blood specifically, you can "bleach" a blood stain
with 3% hydrogen peroxide (available at any pharmacy). The same principles
in the paragraph above apply.

Vince Calder
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