Yes, for an hour. No, nothing replaces paste.
Someone ran household products under a GPU cooler (ComputerBase, relayed by KitGuru, Jan 2023). Ketchup 71C and toothpaste 90C, neither throttled. Cheese, potato, baby cream, copper tape: all 105C, throttled. Real paste in the same rig: Arctic MX4 49C, Corsair TM30 54C, Alphacool Apex 11W/mK 66C.
The word doing the work in your question is 'replace'. Toothpaste is water-based. It dries, cracks, and pulls off the die in hours to days, and it conducts a fraction of what paste does. It fills the gap once. It does not stay.
If you have nothing: a thermal pad of the right thickness beats every food on that table. With no pad either, remount with firm even pressure and keep the run short. Ketchup only if you also hate the board.
Source: kitguru.net, Jan 23 2023, from the ComputerBase test.
