selfbondage Foot-Torture....?

I'm looking for a substance that can cause a strong burning sensation under the soles of my feet as part of a self-experiment in masochism or sensory testing. I've tried 25% acetic acid and capsaicin cream, but both were disappointing—no real intense burn. Clove oil didn't do the trick either. Any suggestions for other topical substances or compounds that might work better? Safety tips appreciated, but I'm aware of the risks. Thanks!