This looks like a viable way to clean up international addresses.
For those looking to clean up US addresses, I would proceed with a high degree of caution.
1. Is the web service CASS certified by the US Postal Service?
2. Will the cleaned addresses resolve to a "DPV" validated address?
3. How old are the addresses on file? If they are older than 6 months, I highly recommend passing them against the US Postal Service NCOA file.
4. Are your staff well versed in the intricacies of US Postal Service requirements and regulations?
I would argue that if you have any question about the four points I make above, you should seek the expertice of a good computer service bureau to perform these address hygiene functions and not "do it yourself".
Some explanations on the above. In August 2007, the US Postal Service requires mailer seeking any type of presort discounts to apply CASS Cycle "L" to their housefiles. This requires mailers have their addresses resolve to a "Delivery Point Validation" or "DPV" address. This means if the address does not match exactly against an address on the USPS DPV database, the Postal Service declares that address undeliverable and you will not be able to take any discounts for mailpieces sent to that address.
The US Postal Service also requires mailers seeking to take presort discounts run their addresses against the National Change of Address (NCOA) database to ensure the most up-to-date addresses for the housefile. This is required every 6 months. As a practical matter, DBA's want to maintain the most accurate addresses on the housefile and ensure that when we need to communicate with customers, leads, etc that our mail gets to the appropriate individuals. The economics of passing the address files against the US Postal Service files, in most cases, will pay for the cost many times over when sending any type of mail such as billings, marketing materials, etc.
If you are looking to clean addresses for any kind of larger scale mailing (ofer a few hundres pieces), not following the items above will cost your organization significantly more postage than is necessary.
Again, I highly recommend seeking the advice of a good computer service bureau to perform US Postal Service address hygiene to your housefile.