How to get built up dirt from floor corners?

Vinegar is typically my "go to" but can be damaging to some surfaces, so I would test first. Murphy's Oil Soap on any wood surfaces.

tooth brush....label it for cleaning only. Denture brushes work as well.

Use a cheap paint brunch and remove as much dirt as possible. Fill spray bottle with water lay towels down and spray until dirt is gone. Usr same paint brush to get excess water out. Works like a charm!

that goes from years of not cleaning corners. Do you use a long foam mop? Use liquid cleaner with an old battery operated tooth brush. And start using a mop that can get in corners.

If you have a carpet cleaner, I would first brush it to loosen dirt, vacuum and then use the upholstry tool on my carpet cleaner.

Shout · Spray

Shout Triple-Acting Stain Remover Trigger's stain-fighting ingredients and enzymes quickly penetrate, break up and remove tough stains. NOT JUST FOR CLOTHES

Spray in corners, let sit a minute or two, take a toothbrush and scrub away dirt.

I use a flat knife and on hands and knees scrap it out then sweep up

TSP aka Trisodium Phosphate it is a Heavy duty Degreaser