Charlie Sheen is of the belief that his ex-wife Brooke Mueller should have her child support payments reduced from $55,000 a month to zero -- and he's using his former 'Two and a Half Men' co-star Jon Cryer's divorce as an example.

Mueller doesn't currently have custody of the kids, who are in the care of Sheen's other ex, the saintly Denise Richards. As a result, Sheen doesn't think Mueller should get any child support payments, especially because all the scratch he does send seems to be spent on rehab and not on actual children.

So where does Jon Cryer come into this?

His ex-wife was arrested for child abuse in 2009, causing her to temporarily lose custody of their kids and her $10,000 a month child support payments, which were reduced to zilch. So in documents Sheen's team submitted to a judge, they state that sets a precedent for Charlie's own situation.

The documents also reveal Sheen grosses more than $740,000 a month, but his expenses total around $90,000 -- because in addition to paying child support and his own bills, he gives Brooke another $30,000 a month for the kids' therapy, medical bills and schooling.

And you thought your kids were expensive.