i advise u to send to nsc less than 30 bucks rather than u do and spoilt it thats my opinion
oh well
a lot of 20 dollars adds up to a lot
do some reading up on the net, ts
searching clubsnap also works
a lot of people here clean their own sensor, me included
i think so far so good, no problem and very satisfied
but if you have no confidence to do it, suggest that you follow their advice and go to servicing centre lor
for me at first i never switch lens much, only have kit , not so much dust
after a while, keep switching,a lot of dust even when i observe proper procedure, i.e. switch in less windy area, turn off camera first, face down, do quickly
i think if i send for servicing everytime it gets too serious i die already, cannot buy anything