Hi this is my first post. I have a large collection of carded action figures. (A 'carded action figure' is a toy mounted on cardboard by means of a plastic bubble. The toy is sandwiched between the bubble and cardboard). So, I store my carded action figure collection in generic cardboard boxes. And I am worried about acids from the boxes eating away the collectible cards. Q1. How can I check for acid levels in the cardboard boxes? I assume that the cardboard boxes are not acid-free. I want to check anyway. There has got to be a backyard chemical 'home brew' that I can wip up SAFELY. You chemical guys are most excellent; however, I do not want to blow my arms off. I am in the process of converting from carboard boxes to plasic bins (those big cheap suckers from Walmart). Q2. Is there any residue (oils) that form on (or ooze out of) these types of plastic bins over time? Q3 & 4 (related to Q2). So, is oil a component of plastic? I noticed that the plastic bins I am finding have an oily feel to them. Is there a way to clean this film off so that the plastic surface is safe for paper/carboard collectibles? Please help.