These two glands are found in the skin and are known as exocrine glands because they have a duct through which the substance travels.
If they do not have a duct and secrete a substance directly...
No. Sebaceous glands produce a grease-like substance called sebum which is excreted onto the skin. They are why you get greasy if you get too far from a shower for a couple of days.
It's a modified sweat gland. Milk is essentially modified sweat, which is produced by mammary glands. Sebaceous glands produce sebum, which is this oily substance designed to lubricate skin and hair....