1. Peel the potatoes and cut them into pieces.

2. Skin the potatoes and cut them into pieces.

3. Remove the peel of the oranges.
4. Remove the skin of the oranges.
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Can we substitute 'skin' for 'peel'?
Are they all grammatical?

Yes, in both instances, they mean the same thing. My mother and her mother used "peel" and my other grandmother used "skin" in these senses.

=)

Yes, you can substitute "skin" for "peel" in these sentences. Both "peel" and "skin" are commonly used to refer to the process of removing the outer layer of something, such as the skin or peel of a fruit or vegetable. Therefore, all of the provided sentences are grammatically correct.

Yes, in the context of preparing fruits or vegetables, "skin" and "peel" are often used interchangeably. Both words describe the action of removing the outer layer or covering of a fruit or vegetable.

All of the sentences you provided are grammatically correct. However, note that "skin" is more commonly used when referring to fruits, such as oranges, while "peel" is generally used when referring to vegetables, such as potatoes. But in practical terms, "skin" and "peel" can be used interchangeably for both fruits and vegetables.

So, to answer your question, yes, you can substitute "skin" for "peel" in these sentences without any issues.