There are various commercial preparations containing phosphoric acid or other chemicals designed to bind to or remove the rust without scrubbing.

Few tools, especially those used outside and for gardening, ever retain their brand-new, never-used look. If they function adequately, why be concerned with appearance changes from time and use?

"If they function adequately, why be concerned with appearance changes from time and use?"

True about teh appearance, but it is functional issue. The roses on the watering cans are diffficult to remove for cleaning (gotta get that debris out to keep unclogged), and the sprinkler is really hard to turn to the different settings -- actually, IIRC correctly it was stuck in place last year so I couldn't adjust the spray pattern, I think a good rust-busting treatment will take care of that.

Hose attachments (is that what you mean by "sprinkler") wear out and may need to be replaced. Watering can heads do get clogged with gunk. Try a toothpick or other poker to get out pieces, and maybe turn it sideways to soak in a small bucket of vinegar or another solution that dissolves iron/rust. Maybe replace it with a plastic one next time.

"Maybe replace it with a plastic one next time."

I really don't want to replace -- they're good old ironhorses (pardon the pun...), they just need a good de-rusting. So, a vinegar soak will accomplish that?

I don't know, it's what I use for things like showerheads but the clogs aren't rust.

Its AI generated but salt/ white vinegar soak and scrub. Neutralize immediately by soaking after the scrubbing with 1c baking soda in a gallon of water .

https://www.google.com/search?q=how+to+clean+rust+off+of+watering+cans+and+sprikler+attachments+oitdoor&rlz=1CDGOYI_enUS1149US1149&oq=how+to+clean+rust+off+of+watering+cans+and+sprikler+attachments+oitdoor&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIHCAEQIRiPAjIHCAIQIRiPAtIBCTI2OTE5ajBqN6gCGbACAeIDBBgBIF_xBfW-qO_CtM-G&hl=en-US&sourceid=chrome-mobile&ie=UTF-8#lfId=ChxjMe

For the watering can roses, once you remove them put a little grease on the threads. The sprinkler control might loosen up with some WD40.

tj

No experience, but naval jelly might help (plus its fun to say).

Vinegar is useful for mineral deposits. Calcium and lime. A long soak in vinegar is supposed to remove rust on metal but it is more of a loosening and scrubbing sort of thing. It is non toxic though

I would stick with those old metal roses. Taken care of they last forever.

There's a nasty powder called Iron Out. Add water, bucket, soak them. I sprayed my cement garden statues that were turning orange due to our Iron from the well water. They look good as new.

Mine get a buildup of minerals from my well water also - I soak in citric acid solution , doesn't take much of the citric acid - it really helps ! Vinegar sounds like a good idea too

Yes the stronger cleaning vinegar and if you add baking powder it really helps.

You can use Coca Cola too. Soak for 24 hrs./ 48 if it is really bad. Scrub and then rinse well and dry thoroughly.

The most powerful rust removers have fluoride based reducing chemistry. (rust is oxidized, so a powerful reducing agent converts it back to a soluble form) This including the spray-on version of Iron Out porkchop mentions, and one even stronger called 'Whink'. Make sure you wear gloves as they can cause deep tissue burns that might not be immediately felt or spotted, especially Whink. The Spruce https://www.thespruce.com/best-rust-removers-4174196 breezily states "Also, be sure to have a set of cleaning gloves on hand and keep a window cracked open. This is a heavy-duty spray with a very strong chemical scent." On hand? They should literally be on your hands!

My lingering question is how did the product affect the non metal components of said sprinkler?