10) The Gemara in Rosh Hashanah (27b) teaches: If a shofar is covered with gold inside, it is pasul. Rashi, Tosfos and the Ran all learn that the pasul [disqualification] is that the sound coming out from the shofar is coming from gold and not from the shofar.
However, the Ritva offers a new peshat and he says that the gold is a chatzizah [makes an interruption], and the sound coming out directly from the shofar, is not coming purely from the shofar as the gold gets in the way. He adds that even a small amount of gold creates a chatzizah and changes the sound of the shofar.
In light of the above, that the pasul is that one is blowing from gold and not from a shofar, or that the gold is a chatzizah, the sefer Chag BeChag (Yomim Noraim pg. 153, he’orah 59) writes if there is a worm in the shofar it’s not a problem, as the main pasul is that the gold changes the sound of the shofar, however, this only happens with gold where even a small amount changes the sound, as the gold is stuck to the side of the shofar and becomes the wall of the shofar. However, a worm is like air or like a piece of sand or mud inside the shofar and it has no effect on the sound coming from the shofar.
Even if chatzizah is a problem, since the worm is not attached to the shofar, the sound goes around it, and it doesn’t make a hefsek. This is the pesak of R’ Elyashiv.
However, based on the above, it would only be ok if the worm is small and doesn’t change the sound, however, if the worm would be big then seemingly it would change the sound. Although it may not be a chatzizah as it is not attached to the shofar, however, it still changes the sound. Tzorich iyun.
