Tim has it nailed. Rimfire Blend can be improved tho if you wish.
1/2 Rimfire Blend, 15/32 Marvel Mystery Oil, 1/32 Kroil makes an excellent .22 rf bore solvent. I don't measure, just dump em in the bottle I carry when it is time to replenish. Shake well before use as it separates. The aroma is acceptable at least to my nose. bob