Taking care of my air blower?

Hello!

I have a giottos rocket air blower.

I bought it about 1,5 year-2 years ago and now I feel that it has somewhat lost its "power".

I dont know exactly what I did wrong but the rubber feels different.

How should I maintain my air blower so it lasts and feels as new as possible?

Also, is there something I could do with my old giottos or Ill have to buy another one?