You never completely detox from anything. Detoxification is generally described in terms of how long does half of it take to be removed. If 1/2 of it is removed in 6 hours, then 1/2 of what's left is removed in another 6 hours, etc. Every 6 hours, you have 1/2 as much as you had 6 hours before. As you can see, if you simply remove 1/2 of it, you never remove all of it. A month is 30 days, say. That is 120 6-hour periods. So multiply the amount of of a 6-hour half-life poison by 1 divided by (2 to the power 120), and you'll see what percentage of it you'll have left after a month.
You'll have the original amount times 7.5 with the decimal place moved 37 positions to the left of where it is above, that is, you'll have .00000000000000000000000000000000000075 times the original amount. This is not the same a not having any, for those of you obsessed with "all-or-nothing " concepts, or "any amount is too much" concepts.