Mix sake, mirin, and soy sauce in a microwave-safe container. Heat uncovered at 600W for 1.5–2 minutes, then let cool.

Heat 2000cc water with 1 tbsp salt to create lukewarm water.

Place salmon roe in a bowl and cover with the lukewarm water. Gently separate the roe from the membrane.

Remove thin membranes and any white residue by scooping from the bottom. Drain lightly and repeat the process until clean.

Repeat the cleaning process 3–4 times, adding lukewarm water each time to remove residue and membranes.

Drain the roe using a sieve and remove excess water completely.