You can create a new column with the following formula...

```
=TEXT(VALUE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(A1,"(",""),")","")," ",""),"-",""),".","")),"000-000-0000")
```

...then Copy + Paste Special -> Values and delete the original column.

**How It Works:**

- The nested
`SUBSTITUTE()`

functions strip out any spaces, brackets, dots and dashes.
- The
`VALUE()`

function converts the result from text to a number
- The
`TEXT()`

function converts it back to text applying the format 000-000-0000. This nicely handles phone numbers beginning with one or more zeroes.

If your input contains any more unwanted formatting, use more nested `SUBSTITUTE()`

functions to remove them.