There was a time when Discover would give you checks that you could use to transfer debt from other cards or accounts, which had a promotional rate of 0% for the life of that debt. I deposited one check into my checking account that filled up my discover card credit limit, then used that money to pay off my higher rate credit card debt. Then I did that a few more times until my entire Discover card balance was 0%. Then I paid off my other credit cards while that debt sat there accruing no interest penalty.
Also, the way the accounts worked was higher debt would be paid off first, so until I fully paid off that account, there was always some 0% debt below all the higher % debt.
There was a time when Discover would give you checks that you could use to transfer debt from other cards or accounts, which had a promotional rate of 0% for the life of that debt. I deposited one check into my checking account that filled up my discover card credit limit, then used that money to pay off my higher rate credit card debt. Then I did that a few more times until my entire Discover card balance was 0%. Then I paid off my other credit cards while that debt sat there accruing no interest penalty.
Also, the way the accounts worked was higher debt would be paid off first, so until I fully paid off that account, there was always some 0% debt below all the higher % debt.