HELP with ancient urine stain that won't come out!
Over the weekend I discovered two very old, ancient urine stains on a somewhat low quality Ikea duvet cover. The item was in a hardly used guest room and I never noticed the stains until yesterday. One of my cats must be very proud of his or her accomplishment! The stains are clearly at least a year old - no odor, just an impossible yellow stain that won't come out. I've tried everything... soaking the stain in pure hydrogen peroxide w/ a teaspoon of detergent and enzyme booster added. No effect. I soaked it in a hot solution of sodium percarbonate. No effect. I washed the item at 140 F using Tide HE w/ Bleach powder with sodium percarbonate and enzyme boosters. No effect. I soaked the stain in vinegar. No effect.
Nothing I try does anything to fade the stain. It's almost like the yellow has bonded with the cotton and changed its fundamental color. The fabric acts as if it has been dyed, rather than as a normal stained fabric where the stain can be removed. I feel like I've tried everything... does anyone have any suggestions?
And for my own peace of mind, I need to disclaim to everyone that I have a very clean house and was horrified at the discovery. I adopted an injured outdoor cat about a year ago, and she adopted this room as her own. I suspect she peed there a couple of times out of insecurity or due to the change to being an indoor cat. Just two spots. But I'm just mortified having to post about this in public!
If I can't clean the duvet cover I will probably just use it as a workshop towel or pet bedding, but I'd like to exhaust all possibilities first. Thanks everyone!