6. Machatzis hashekel. One should not give machatzis hashekel from maaser money. This is because once the minhag to give machatzis hashekel on Erev Purim was accepted by Jews worldwide, it became like a chiyuv (שו''ת מהרי''ל סי' נ''ו אות ז', של''ה ריש מס' מגילה ד''ה כל דבר הובא מג''א סי' תרצ''ד סק''א ).
7. Matanos l’evyonim. One may not use maaser money for his basic chiyuv of matanos l’evyonim since it is a full-fledged chiyuv (מג"א סי' תרצ"ד סק"א ). However, once he has fulfilled the minimum mitzva of a gift to two poor people, he may use maaser for anything beyond that. Similarly, if one gives to various mosdos and organizations, which are not considered matanos l’evyonim, he may use maaser money (שו"ת שבט הקהתי שם ).
8. Kimcha d’Pischa. One may use his maaser for “kimcha d’pischa.” Back when each town set a sum of money as the required kimcha d’pischa, one could not use maaser money, but nowadays there is no fixed amount, so it is all tzedaka (הגרש"ז אוירבאך, מעדני שלמה עמ' ב' ,מו"ר שו"ת שבט הקהתי ח"א סי' קל"ז ).
9. Kaparos. Maaser money should not be used for kaparos during the Aseres Yemei Teshuva, whether one uses an animal or money, since kaparos are a chiyuv (מ"ב סי' ת ר"ה סק"ו ). Anything beyond the chiyuv may come from maaser money.
