On 11/11/2011 15:36, john east wrote:

Have an ordinary house smoke alarm. It's about twenty years old and it has

Assuming it is an ionisation style detector, then just throw it away and
install a new one.

These things have a maximum useful life of around 10 years. (modern
alarms are marked with an expiry date)

recently gone off in the middle of the night for two days running and for no
apparent reason.

I've heard that it might need a vacuum cleaner applied to it. Is there
likely any truth in that, or is there anything else i might usefully do?

Or does it probably mean that I have to replace it?

Definitely. Your life may depend on it.

--
Cheers,

John.

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