Mattress cleaning...?

We have an old mattress...one that needs to ascend to mattress Heaven and prance in the fields of clean linens.  When it goes it can take the pillows with it.  However, a new mattress is not in our budget right now and is the least of our worries.  I came across a way to "clean" our mattress on Pinterest.  Even if it was pure crap I did it and I will continue to hold on to the placebo effect that it really did clean our mattress.

It said I needed baking soda (about a cup) and an essential oil like lavender.  Honestly, I didn't have any essential oils (hangs head in shame, I know! I know!) but I did have a lemon! They get oils from the lemon rinds, right? Well, I went with that idea and just used my micro-grater and grated the yellow from the lemon and mixed it in.  Whatever, it smelled good.
After mixing my concoction I sifted it onto the mattress and let it set for an hour then came back and vacuumed it up.  Clean mattress! Right...At least it smelled good.