For the chrome areas I use simichrome polish, works good.
I also use simichrome polish for the non-chrome areas that I can reach.
Problem is, there are a number of nooks and crannies that are hard to reach and that's what takes up the bulk of my time.

If it were my pickup (that I painted flat black) that would be no problem since I can just shoot the rusted area with the rust reformer spray.
This spray only comes in flat black.

Is there a version of this that is "colorless" that I can just point and spray? That would save me gobs of time.
Assuming not, based on my initial searching, maybe the alternate question is "what's the most efficient method you've found to get rid of rust in a number of hard to reach places (where you wouldn't want flat black spray to end up painting the surrounding parts)?"

 

There are rust converters that are more a brush on liquid and not a paint. They are intended to be brushed on to convert the rust then the painting is done as a separate step. Another option is to use a rust preventing oil like Boeshield T9.

 

I found naval jelly works well

 

Navel Jelly is a rust dissolve so when it's done it's job you have bare metal that needs to be treated/coated or the rust quickly comes back.

The converter that you show, which I have not seen in aersol form, converts and technically self protects.

A great brush on version is called Rust Mort, have been using for 25 years!

 

Home Depot didn't have it or anything similar.
The local Auto Paint store recommended Mar-Hyde.
Supposed to turn the surface black but when I applied it it came out as a creamy colour.
I'll give it some time to see how good a job it did.

 

I have a product I have used for many years with great success. Autozone sells it as " Loctite Extend Rust Neutralizer" When I first used it, it was labelled just "Extend" but I was amazed at how well it worked 40 years ago, and still does today. It works better on light rust than on bare metal, and it disclaims on the can "Some rust must remain for the product to work" It turns the rust left after a light sanding to a black color, which can be painted the color of choice afterward.


Try it, it is in the body filler section of the store.

 

Two different products I recommend for two different types of rust and corrosion control.

Rustoleum Rust Reformer:
https://www.rustoleum.com/product-ca...rust-reformer/

Waterbase primer / rust conversion, Knock off the large scale rust chunks and flaking, exploding rust and paint it on over the rest of the rust. actually works better on rusty metal than clean new metal as it grabs and converts steel corrosion (iron oxide) into neutral Iron sulphate. After it cures and dries well, you can topcoat right over it like a primer.

Fluid Film:
https://www.fluid-film.com/
I have a 4x4 and the guys are all over this stuff... so much that I had to try it/

I have been sampling and experimenting and I have sprayed it on the boat trailer leaf springs, one of the most corrosion prone substances know to man and fish...

It will free rusted bolts and treat them so they will nary rust agin!

The 4x4 guys treat the undercarriage as rust proof, lawn mower guys use it to stop the grass from sticking and decks from rotting out.

I got mine at advanced auto supply $12.00

Cheers!