I take the spools off my ice reels and set them in a bucket or very warm soapy water for an hour, then I rinse them off in another pail of very warm water.
One at a time I put the rinsed spools back on the respective reel and peel off about 75 feet of line while it is still warm and soft. I close the baoil and re-wind the line pinching it lightly in a folded piece of suede leather.
This removed dirt and oils plus it removes a lot of little kinks and things that can lead to twisted lines when they are used in the cold. When I re-reel the line I pay particual attention to the line running thru the leather’s nap [rough] side. If I feel the line snagging or stuttering as itt passes thru, the line gets removed and new line goes on. OR, if the line was fairly fresh last winter when it was last used, I’ll walk all the line off outside and re-fill the reel with it starting with the used end. This puts new line at the user end for this season but you will need to repeat the soaking in warm water and reeling it thru the leather to get the tight coils out of it.
When you stop and think about line, its really not that expensive. I clean mine as way to see if the line has any knicks or knots. I won’t hesitate to replace line instead of dinking with all the other stuff including chemicals.