differences - "Back to where" vs "back where"

Is it grammatically okay to omit the "to" in the following sentence?

1) Put something back to where it belongs

2) Put something back where it belongs

What's the difference between them? which one of them is grammatically correct?

Similarly we have these 2 sentences

3) Go back to where you came from

4) Go back where you came from

any help will be appreciated

Answer

Oops, I meant to post this as an answer, not a comment...

Sentences 2 and 4 are correct. Though it isn't a hard core rule of grammar, brevity can be a useful guide. Even people who speak English as a native English often tend to insert words that aren't really needed - to, of, etc. As a general rule, it helps to try to say something with as few words as possible.