@Sachin,

I agree that the CLR Regex method should be the fastest although I've not seen any performance testing on it.

The questions I have for you is...

1. Can you use CLR or do you need a 100% T-SQL solution?

2. Is the maximum length of the data <= 8K bytes?

I no longer believe this. In the last 2 weeks, I've seen CLR Regex get its doors blown off by more than one example of some good, ol' fashioned T-SQL. CLR is still the fastest for splitting a string and it might be the fastest for cleaning a string, but CLR Regex probably won't be. Regex itself seems to have been over promised and under delivered. It appears that you pay in performance what you thought you gained in flexibility.