Use a smidgen of match and a pinch of probability. Capture cards by matching or adding cards from your hand, then count the ingredients and measure the powers. A splash of strategy, and the potion is magic!
Here are reference cards for the 1995 version of Frog Juice. These explain which cards are power cards since this version did not have the "P" printed on the cards. These reference cards also explain "special action" cards too.
Since future versions included Black Cat and All Purpose Witch Wash as power cards, I also included them on the reference cards. Hence, the total number of power cards is increased from 15 to 17 for an extra bit of fun.