Adam Funk wrote:
On 2013-12-07, polygonum wrote:

Mr Medway or anyone else, do you have any advice on removing blood marks
from off-white wool-blend carpet?

Although quite some attempt was made to clean them up at the time,
various circumstances have resulted in them still being visible some 3/4
weeks later.

(No criminal aspect to this! Illness, unfortunately.)

Hydrogen peroxide (probably still available from your local
chemist's). As with any cleaning tactic, it's worth testing a little
of it on a hidden area first in case your carpet disagrees with it.

Oxalic acid is quite useful for iron based stains in wood. effective but
not too aggressive. Might work in this instance.