Crab Grass

[SamIAm]

I use my grass clippings in late summer and fall to make compost. I try to use very little chemicals however crab grass becomes a real problem. Besides killing my grass the crab grass seeds end up in my compost and eventually in my garden making weeding a chore. I have been using corn gluten but it does not seem to be nearly as effective as pre-emergence. Would using the synthetic pre-emergence in the spring and early summer adversely effect my compost if I use the grass clippings a couple months later? Any advise is appreciated. Thanks.