<===> input.scss
$x: ecks;
$y: why;

div {
  blah: "hey #{$x} ho";
  blee: hey#{$y}ho;
  bluh: "foo #{$x}";
  bleg: foo#{"hey"}bar;
}
<===> output.css
div {
  blah: "hey ecks ho";
  blee: heywhyho;
  bluh: "foo ecks";
  bleg: fooheybar;
}