Can you use your own old published essays as college essays?

I’ve written a decent amount of personal nonfiction in the past, and a lot of the material I’ve already written would fit as college essays. But some of the material I want to use has been published in various places–I’m wondering if it’s still all right that I use those old essays (though modified a bit)? My fear is that a college would enter a sentence of my essay and see that it has been published online somewhere and think that I’ve plagiarized it (because my application would be anonymous when they see it). Or maybe they would think that I’m lazy for not writing a whole new essay?

Nothing like finding out that the love letter you received from your BF/GF is verbatim from a letter he/she wrote to another love interest years ago…
:-*