Solar ovens will absolutely NOT sterilize fertilizers. They _do_ kill most of e.coli and listeria bacteria, but plenty of bacterial spores will survive. It also

Solar ovens will absolutely NOT sterilize fertilizers. They _do_ kill most of e.coli and listeria bacteria, but plenty of bacterial spores will survive. It also will generate dust, that can be deadly. Instead, you should keep the fertilizer in a heap under some straw. This lets a mosty-non-pathogenic microflora to get established and eat pathogenic bacteria.