Does leather that is naturally colored (not dyed by humans) contract tzara'at?
Halacha 1 states: even leather that is colored naturally (by heaven) is susceptible to impurity because of blemishes. This is unlike garment fabric where color exempts from tzara'at.
Question 2
Camel's wool and sheep's wool are spun together in equal quantities. Does the resulting fabric contract tzara'at?
Halacha 3: when camel and sheep wool are equal in quantity (half and half), the fabric contracts impurity due to blemishes — the majority rule applies, and equal is treated as susceptible.
Question 3
A sail from a ship made of linen — can it contract tzara'at?
Halacha 6 explicitly lists a ship's sail as susceptible to tzara'at blemishes — any article fit for other forms of ritual impurity (even if not susceptible to midras) can contract blemish impurity.
Question 4
A definitively impure garment becomes mixed with 999 other garments. What must be done?
Halacha 15 states: when a definitively impure garment becomes mixed with others, ALL of them are deemed impure and must be burned — even if one is mixed with several thousands.
Question 5
From where must blemished garments be removed?
Halacha 17 states: blemished garments are sent outside cities regardless of whether the city is surrounded by a wall — this is noted as a stringency in garments over humans (humans are only removed from walled cities).