Car seats and wee - help!

[SweepTheHalls]

I have been given a well used ( and potty trained with!) group 1 car seat. I have washed the covers with vinegar and managed to get the smell out, but the plastic shell, polystyrene fillers and crotch buckle ( which doesn't look like the fabric can be removed) still smell despite bleaching and fabreezing. Any ideas how else I can get the smell out?

You can get a spray (I got mine from Tesco but can't remember what it's called) for getting animal wee/sick smell out of things. My SIL recommended it when their cat used to puke over their bed when it was poorly (bleurgh). If it will deal with that smell though I reckon it's worth a try? It was a white spray bottle...

Thanks for that!