Borax has been the best way to keep eggs ready to fish for 40 years.
The only way to make it better is to use a little Beaumac red dye and salt in a plastci bag and let them sit for a day in the refer. They will turn into goo and then re-absorb all the juice. Rinse and put up with Borax and you have eggs that will last a long time in the river and even longer in the Freezer because the egg sacks will not freeze hard and there will be no ice crystals inside the eggs to pop them. You cna freeze them and then take them out and they will bend like rubber until thawed.
I am fishing 2001 eggs that look as good as the day I put them in the freezer.