babyface1968

How do I remove the obselete Firefox entries? Like when I click tools and Firefox and click for example on Java Console 6.0.21 or 6.0.22 or 6.0.24 I can not delete them and many more old entries that are older than newer ones etc.... I have CCleaner 5.08 64-bit and Firefox 40.0.3 using a Dell Inspiron 7746 with windows 8.1 64-bit.