Backhousia citriodora ). [8] However the oil may irritate normal skin at concentrations of 1%. [9] [10] [ edit ] Over-the-counter substances For mild cases, over-the-counter wart medicines, such as salicylic acid may shorten infection duration. Daily topical application of tretinoin cream ("Retin-A 0.025%") may also trigger resolution. [11] [12] These