Is it possible to crack a salt from hash with or without cleartext?

Hi,

I'm wondering if it's possible to crack a salt for a hash given the hash and possibly the cleartext.
Say for instance I have an appearant MD5 hash list that does not resolve and I suspect it's salted with a static salt in for instance PHP code, is it possible to bruteforce the salt given a good wordlist for which I suspect some salts should resolve to, or if I know the cleartext and hash and be able to bruteforce the salt?

Hope you understand my question. 

Best regards,