Bit of a mix really,found this under a bed in a 2 bed eot,also another big square patch under a sofa in the lounge.
Tenant had attempted clean with a rug doctor,carpets smelt mouldy,brown marks look like blood,some may be from furniture rust marks,where it`s not been isolated,others from around a shrine,place stank of curry,and not in a nice way,stale and minging !!!
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Pics not the best,but you get the idea,think it`s going to be a job for the carpet fitter,didn`t really make much of an improvement.