What's your preferred method for cleaning stinky plugs / drains...?

[givemegravyonemoretime]

...bathroom & kitchen....?

Happy to consider chemically, branded stuff, or lentil-weaving lemon slices and sage oil type approaches. Whatever works.

I like those black bottles, I can't remember what they are called unfortunately. I flush mine through with a big bowl of hot soapy water once a week though.
Full to the brim and then let it go! Weeeeeeeeeeeee!
(My theory being, that a large amount in one go will swish everything down the u bend and then leave a nice seal of clean water behind.)

Caustic soda if the drain is blocked, bleach for regular cleaning.

Weekly, fill the sink with hot water. Add 2 tablespoons of washing soda (about 90p per kg from the supermarket), pull plug and let it run down. Washing soda is an effective degreaser and keeps the inside of the pipes clean (and is much safer than caustic soda).

IME sinks used regularly should not really smell so the smell may be coming from the overflow so I'd squeeze a small amount of neat bleach through the overflow hole.

Oooh thank you.

Would washing soda be in the aisle with laundry detergent etc?

Where would one buy caustic soda?

Yes caustic soda is really nasty stuff but it does clean well. Makes you are wearing gloves. Its available from most supermarkets in the cleaning aisle.