Starter motor cleaning

Hi, my bike has been hard to start. Some times it fires right up other times it is like the battery is weak.

I took the starter out and took it apart, lots of pieces of the brushes fell out.

The manual says to clean with a high-flash Solvent. Can some one tell me what to buy to clean the inside of the starter with?

Thanks

The manual probably is refering to electrical contact cleaner. It dries very fast and leaves no residue when dry.