Sennheiser SL Headmic 1 Instruction Manual page 13

Care and maintenance
Rinse the connector and the socket with isopropyl alcohol to
remove the remaining salt deposits.
Dry the connector and the socket using a soft cloth or a small
piece of cotton wool and carefully tap them off.
Allow the connector and the socket to air dry for approx. 1 hour
so that the remaining isopropyl alcohol can evaporate.
Slide the silicone tube onto the connector.
Connect the connector to the socket.
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