Depending on size. But about a year they become juveniles or around 4 to 6cm. I believe again varies depending on growth rate but about 10 years they are done growing. Also after 6 to 8 cm or 5ish years you'll be able to tell the sex of the tortoise.
Like Tom said if it's not been heavily soiled. You can clean it by just soaking and rinsing or you can use a tort safe soap. I don't know the brand of cleaner/soap but I'm almost positive that there is one.
They need to be separated. They both need their own enclosures. The female is the alpha in this situation. And apparently has had years to abuse the male.
You might try contacting gorilla glue company themselves. Thanks to the lady that used their glue to hold her hair in place a year or so ago, this won't be the weirdest thing they've encountered.