Johnson's Car Nu

Given that I’d think the labeling might have changed over the decades between prewar packaging and whenever plastic bottle caps became common; my bet is old bottle new cap to replace the old metal one that rusted out.

I’d also note that that cap looks like it’s a childproof one that’s been modified, which would put the cap even closer to now than whenever plastic bottle caps became common.

CMC fnord!

Here’s the reply from my follow-up question:

In the 30s & 40s, colored Bakelite was used in many household objects - appliances, kitchen tools, radios, etc. and is notorious for fading so I think your bottle was kept out of direct light for a long time.