After steaming it is always important to wipe down the steam wand and then purge some steam or water through it. If you don't, the wand can get caked up with milk which is not sanitary, and the steam tip can get clogged up.
See this article for instruction on how to clean the steam tip: Gaggia Classic Maintenance
Failure of normal wear and tear items such as group gaskets, seals and shower screens are not covered under warranty. Issues due to scale build up or lack of maintenance are not covered.
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