Help with seedlings, millions of 'em

[Peach]

We do a maintenance contract. Lawn is in it's second season, so it's not too thick, shade is a cahllange, and there are literally a hundred thousand or more tiny seedling trees in the lawn. (Plus the substantial mulch beds.) They look awful. What can I do to rid the lawn of them? This is a multi million dollar property and the type of situation where if I don't do this correctly I can lose the customer to a fast talking competitor.
Peach

[joshua]

most of the seedlings die off when the weed control is sprayed, if not after a few cuttings. its nothing major to worry about.

[CSRA Landscaping]

Spray them with three way or three way plus quicksilver.

[Peach]

Thanks guys...I was hoping it was that easy
Peach