This forum hasn't had a post for a while, so it's obscure information time. Been using tea as a 'toner' for some years, but I thought I'd try it with some RC paper. Got good results with 1 teabag in a litre of boiled water. Let it brew for 5 minutes or so and then let it cool to 20c. A nice ivory tint was imparted to Ilford MGIV RC after about 3 mins. Don't overwash the prints though or you'll remove the stain.
For those who like to mix up their own chemistry, I can recommend Ilford ID-78. A good substitute for Neutol WA. Not as warm as the Harman warmtone dev. but the working solution lasts quite a bit longer. If anyone is interested, I'll send you the formula (don't all rush at once)