i have had this 23mi bottle of Tamiya Clear Yellow Acrylic for many years. i use it for cab light, turn signals, & side marker lights on my builds. its got down to about a 1/4 of a bottle and thicken up. i know this question has been ask before and i should know the answer but at my age sometimes i forget to putt my teeth in when i go to the store..what can i thin it with beside buying thinner ?