Sentence:  Some schools might have an art studio, an area of forestry in the playground, or a performance stage in the hall – all exceptional assets. Just check they get plenty of use and aren't <WSD>mothballed</WSD> while the school concentrates on (you guessed it) maths and literacy. 
Meaning of the word marked with <WSD> tags:  To stop using (something), but keep it in good condition.