The only card which removes poison counters, Leeches, uses the text "target player loses all poison counters", which is analogous to loss of life, as opposed to "remove all poison counters from target player", which is how the game treats eliminating counters on permanents. However, when it comes before the colon in an activated ability, "you lose X life" is replaced with "pay X life", the difference being that you can't pay life you don't have. Also, costs like "Discard a card:" or Sacrifice a creature:" never mention "you" or "yourself", it is implied that you are the one paying the cost.
Keeping in mind that you should only be able to activate the ability if the cost can be paid, how would you word the following cards?
Infectious Fumes 1BB
Enchantment (uncommon) 2, remove a poison counter from yourself: Put a -1/-1 counters on target creature.
Ichor-Mad Leech 1G
Creature - Leech (uncommon)
Remove a poison counter from an opponent: CARDNAME gets +2/+2 and gains trample until end of turn.
1/2
Keeping in mind that you should only be able to activate the ability if the cost can be paid, how would you word the following cards?
Infectious Fumes 1BB
Enchantment (uncommon)
2, remove a poison counter from yourself: Put a -1/-1 counters on target creature.
Ichor-Mad Leech 1G
Creature - Leech (uncommon)
Remove a poison counter from an opponent: CARDNAME gets +2/+2 and gains trample until end of turn.
1/2
CubeTutor Link
2: Remove a poison counter from yourself. If you do, put a -1/-1 counter on target creature.