How can we escape from the Sandbox?

So we can hope the site is needed approximately six months and Good Back links& Unique Contents.

 

I have 2 sites that have disappeared from the rankings in Google altogether and can only think it must be this phenomenon 'the sandbox'.

Black hat techniques are unlikely from me as I am not experienced enough to know how to do those, yet it is possible in error!

Is there someone out there interested in taking a look at my sites to give some advice?

Thanks