Objects created in immortal memory are never cleaned up and live for the application's lifetime.

在不朽内存中创建的对象从来不会被清除，在应用程序的生命周期中一直存在。

youdao

The "Grace Darling", as it became known, had been on show since 1938, but was never cleaned to museum conservation standards.

BBC: NEWS | UK | England | Tyne | Historic sea rescue boat restored

But the devil came in his studio and found his glasses and then by breathing on his glasses and cleaning them with his jacket - or with his handkerchief or whatever, he cleaned the glasses in a way that they had never been cleaned before.

NPR: Singer and Songwriter Neil Young

They never share supplies, and all items are meticulously cleaned by teachers after each use.

CNN: Giving a childhood to young cancer patients