I described how to prepare a whole squid in my squid noodles recipeso please refer to that. Salt the intestines after you take them out! Be generous with the salt, as shown in this photo!

https://cookpad.wasmer.app/us/recipes/167981-squid-noodles-ika-somen

If you leave the guts overnight, a lot of moisture will come out of them.

Use the remaining half of the squid body (peeled) after making the squid noodles.

Make small cuts in the membrane of the guts and take out the contents. To make it smooth, chop up the contents finely or pass them through a sieve.

I just use it as-is.

Taste, and if it's lacking flavor add some soy sauce or salt! Flavor it to your liking.

If you are going to make salted squid intestine instead of shio kara.

After leaving the salted guts overnight and letting the moisture come out of them.

Wash off the salt, and go back to Step 7. Salt it again, and repeat Steps 7-9. After a week to 10 days you'll have salt-preserved squid intestine. It tastes delicious, like salt-preserved sea urchin. It goes so well with plain rice! If you freeze it and slice it thinly, it's a perfect sake snack!