Exhausted fixer stuck to plastic beaker

[Samuel Hotton]

I stupidly left some very EXHAUSTED film FIXER in a clear PLASTIC measuring beaker for about a week. When I dumped it out, the inside of the beaker is coated/plated with a opaque black silvery material. This coating does not want to wash out. I do not want to scrub it out with a abrasive material as it will scratch to inside of the plastic beaker.
How do I clean this material from my beaker please.
With thanks,
Sam H.

 

[domaz]

Just throw it away. It's a plastic beaker- not exactly the end of the world here. Even if you get it clean enough for your eye you will never be able to trust it again.

 

[glbeas]

Photographic bleach will eventually remove the silver that plated out of the solution. If you have some from a sepia toner or color process leave it in there after you use it and see what happens.

 

[phaedrus]

Next time, throw a nickel in there to silver-plate it.

 

[Lowell Huff]

Sodium or Potassium Hydroxide solution will disolve the residue.

 

[fschifano]

Potassium Ferricyanide bleach, the same thing that comes as part A of many sepia toning kits, will convert the silver to a halide. After that, you'll need to dissolve the halide with some fresh fixer, and don't be surprised if it takes a while. Toss it all out in the end, and wash the container. Any silver left that's plated onto it after that treatment won't be very reactive with anything else either, so don't worry about it.