ok i have a 91 chevy lumina... the flippen back dash behidn the back seats, the lil capeted peace of fiberboard? rattles like hell... was wondering if theres any kind of cheap spray i can buy to spray udner it to stop it from rattling, they have sound damperign spray at pepb oys for 20$.... just seems like thats too much. would anything like rubber spray work or under/over coat? somethign that wuldnt smell bad would be nice, thanks.