We had a safeik treif bowl that was waiting to be kashered. The bowl was accidentally used to make macaroni in a microwave which was then eaten with silverware.
Is the microwave treif?
Is the silverware treif?
I am assuming that the bowl was not used in 24hrs.before it was used for the macaroni. The rule is that although we have to kasher any kli that becomes treif, nevertheless, bdieved if it was used, it will not make other things trief. Therefore the bowl and the microwave are not trief now,and may be used.