help with .htaccess?

I have an issue with pages from our old web site still being found by the Google web crawler. The old web pages were .asp . Of course
Google does not find the pages and so I get crawl errors. The good
news is that I am still getting very good page ranking. The bad
news is that I don't like seeing the crawl errors.

So, here is the .htaccess question. Can I write a generic
301 redirect, or a rewrite condition, using a wildcard that will
redirect all of those old pages that contain .asp in the page?
And if I do, will it obviate the 404 errors that Google is seeing?

If the answer is to the affirmative, are there any .htaccess experts
that can help me with the code?

Thanks for the help.

Actually, it looks like it is BEST to just use the ErrorDocument 404
instead of using a 301 redirect of the dead pages. A 301 redirect
of dead pages can cause a lot of problems with the search engines.
So I will leave things as they are.