Reply to replacement jog wheels

i took off my jog wheels to remove grips that were put on when i bought it and after i had cleaned it, i realised it had developed little crack all around the plastic( i believe) clear jog wheel. its fully functioning still but just doesnt look to good although you cant tell unless your lookin fairly close at it. id like to get another one but ive had no look finding replacement bits.
any help appreciated.
http://www.youtube.com/watch?v=bvcR9...watch_response
there is a pic at the end of this midi fighter competition mix(me and my bro). there is a still pic at the end which shows the cracks in jogwheel(left one)