Probably the side without the disposer since there are more crevices. However, pouring grease down the drain is NOT a good idea. It can cause a variety of problems in your pipes, your septic or for the water treatment plant. Pour it into a container and put it in the trash.

Put a metal coffee can or tomato can (or other vegetable) next to the sink. Pour as much grease as possible into that. Discard with garbage. What's left, wash off with soap down non-disposer side, so it won't also gum up the disposer.

yep, pour it in a can and toss that inthe garbage.

i had my septic system pumped this past spring. the previous owner must have poured grease down the sink on a daily basis. the 4" line fromthe house had about a 1" hole thru it the rest was solid grease, the tank had 2 large chunks of grease in it, each the size of a 55 gallon barrel, plus all sorts of smaller chunks.

grease will only stay liquid for a little bit inthe line, even then it is coating everything it touches and eventually dries rock hard.