how do I clean urine stain on underside of plastic toilet seat?

I have plastic toilet seats. There is a yellow urine stain on the underside of the toilet seat from backsplash. I can't remove it! I've tried cleaner with bleach and that takes care of most of it, but not All of it. I would love to take a scrub brush to it, but don't know what is safe to use on the plastic. If I use a regular hand held scrub brush, do I have to keep it for just this use exclusively? And once I get the stain removed, how often am I supposed to clean the toilet seat to keep it from coming back?

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It doesn't come off with water, needs some chemical attack. I've used mild lye solution. First, spray water on the area. Apply lye solution (1/4 tsp of lye into a cup of water) with a brush, wait a few minutes, rinse (water spray again) and mop dry. Rinse out your cloth and the brush, or lye will attack it. And use gloves, of course.
I don't know what the stuff is, but the lye treatment seems to only be necessary a couple of times a year (soapy water is the usual cleaning medium). My seats are painted, so the paint will soften if I overdo the lye (but plastic is not affected).

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Ick. Why not just buy new seats? For the cost of what hasn't worked so far, you could probably replace the seats.

On Thu, 10 May 2007 00:01:08 -0400, snipped-for-privacy@webtv.net wrote:
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With wooden ones.

On May 24, 12:43 am, snipped-for-privacy@adelphia.net wrote:
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You could try white vinegar to clean it. Put it on neat with a cloth and leave it, then wash off with hottish water. You should clean your toilet and seat daily to keep it clean!!!

You can go to a discount store and buy a new toilet seat for about $20-$30. I really do recommend a good quality thick hard plastic---not padded plastic or the flimsy ones hotels use. I favored wood forever, until I had to buy plastic one time, and I really wouldn't go back to wood. The plastic cleans more easily. The cleaning process eventually causes the underside of a wooden seat to deteriorate, and at that point the wood becomes more porous and harder to clean.
I raised two sons, so I could probably be paid as an expert witness. :-)
Warmest Regards,
Donna

I tried all the recomendations on this web site and used the good old Brillo pad and it removed all stains.u

replying to robsonsusan2, Tracy Needle wrote: Brillo pad absolutely genius

replying to Tracy Needle, MyUserName2019 wrote: Worked here but a lot of elbow grease.

replying to robsonsusan2, mommydore wrote: Worked like magic!

replying to Donna in Texas, HarcX wrote: Donna, Look at the question, the need is to remove the urine stains NOT to buy a new seat. I'll be very brave and hazard a guess the idea of buying a new seat has actually crossed the mind.

replying to HarcX, Rosey wrote: I have the same problem. I would replace it but my toilet seat costs $250. It is a curved seat that is a special order. I will try vinegar and baking soda before I buy a new seat

Vinegar doesnt work for t seat

On Tuesday, September 1, 2015 at 1:58:25 AM UTC-4, snipped-for-privacy@gmail.com wrote:
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That's just incorrect. Sorry.

Hey use bicarbonate sodda n white vinger. Make in to a thick paste and apply with tooth brush to seat. Rub in and be amazed. Leave 5 mins or a bit longer snd clean off. White n as new!

replying to bana197878, pepsicola wrote: worked a treat although just used the vinegar i had in my cupboard

replying to bana197878, dieuwka tsesmetzis wrote: Thanks very much for your advice,toilet seat was clean in minutes!

replying to kara849, Cal wrote: At £25 + for sa new seat I’d rather try cleaning it first (ick!)

replying to whit3rd, Eureka wrote:
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Hi, I took the seat off and soaked it in a large tub of hot water and very concentrated vanish napisan oxi action. It's enzyme not bleach based powder. Guess what? Sparkly white seat. Can't believe it. If you saw how filthy it was, it's quite remarkable. No scrubbing, spraying, and the whole seat gets the whole clean at same time. Nice.

replying to Eureka, Bella wrote:
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was,
whole
Thank you so much. I thought I had tried everything but obviously not as this worked. I don't know how to take the toilet seat off this one as it is different to our old one, so I put the Vanish Napisan into a bowl with hot water and made a sort of runny paste wiped it on with a damp cloth and let it sit for about 10 minutes. I then got a scourer and scrubbed. Now for the first time in a while I have a beautiful clean white seat.