You'll want AHA, BHA, Retinol, or Urea in high concentrations if physical exfoliation (dry brush or scrub) doesn't do the job for you. It really depends on what your skin responds to so it's a bit trial and error. Also requires a bit of experimentation, Urea works well in combination with Lactic Acid (AHA) but it may be that you respond better to Glycolic (also an AHA) or Glycolic in combination with BHA, etc.
Personally, dry brushing and Retinol works best which is a pain because for the body ideally, you need higher concentrations of Retinol which would only be available on prescription. Lactic acid is a close second and they're also the two actives my face responds to best so I do think that is somewhat indicative.
The most potent thing I think available is a 30% Glycolic and Vitamin C body lotion (think it's called Advanced something) from Eneomey (older version spelt as Mene & Moy) but you have to get the 15% version first (called Revitalising something) then build up to the 30% and use SPF if you'll be exposing the area to the sun. I think it's about the same price as the Paula's Choice and I'd rather get the higher % that you can potentially use less often and isn't swimming in silicones, but probably best to try and see if your skin responds to glycolic well or not with a cheaper product with a lower % like Nip & Fab pads or similar first. The olay toner mentioned above is a cheap BHA but I believe it's no longer being sold.