I spilled a harsh chemical on my big toe a couple years ago and now it's only numb in the top corner only & rest is fine. could it b from the cleaner?

Remote exposure: If the numbness has only started now it is unlikely to be related to a chemical exposure from two years ago.

Maybe (not) . . .: Yes, I suppose harsh chemical spilled years ago on your toe could make part of it numb. But since you didn't mention specific chemical, I can't give you more specific reason. However, it's also more likely that you're describing diabetic neuropathy. Even vitamin B12 deficiency can cause numbness & tingling. Nerve entrapment, too eg tarsal tunnel syndrome. Bottom line, go see your Family Doc.