Fix / clean or throw away tire with 30+ thorn punctures?
When you remove all the thorns very carefully you could keep using the tire. Unfortunately this might be some hassle with 30+ thorns and you can not be a 100% sure that you really have removed all of them. Also some may have broken off in a way that you see the remains from neither inside nor outside but the remains may be pushed further inside after some time of usage causing a new flat.

Therefore my advice would be: If you can afford it you're better off with a new tire.

If you want to save the money, try to very carefully remove all the thorns you see or feel. Especially on the inside you should check the tire with your fingers if there's something sticking through. Even then you will have to look out for a higher puncture probability that means you should be prepared to deal with it, i.e. carry an extra spare tube and a repair kit if you don't do this already.