#MATL, [<s>22</s> 21 bytes by Luis Mendo.][1]

Finally... MickyT cracked it while I was writing an explanation, so his answer is the "valid" one. I posted this anyway, in accordance with [this meta post](https://codegolf.meta.stackexchange.com/a/10578/31516).

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`M` and `Y` are unnecessary and are commented out. It's enough to add 4 whitespace characters, not 5.

 t' @ *'dm1e5%M
 dw%Y
 (

This is equivalent to the [more compact][2]:

 t' @ *'dm7dw(

**Partial explanation:**

 % Implicit input
 t % Duplicate input
 ' @ *' % String with ASCII-values [32 64 32 42]
 d % diff, giving [32 -32 10], 32 is space, 10 is newline
 m % ismember, checking if the character is 32 or 10
 1e5 % 10000, but could just as well be 7
 d % Taking the diff of the scalar 1e5, returning an empty matrix []
 w % Swap stack in order to use ( below
 ( % Equivalent to x(y)=[], where x is the input string, and y is the logical
 % vector found using ismember (m)
 % Implicit output


 [1]: http://codegolf.stackexchange.com/a/103210/31516
 [2]: http://matl.tryitonline.net/#code=dCcgQCAqICdkbTdkdyg&input=WydUaGlzIGlzICcsIDEwLCAnYScsIDEwLCAnc3RyaW5nJ10