Possible Clues:

• An acid test, perhaps, for this paper?
• This will show if it's a CID matter
• Acid-alkali testing substance
• Test paper too hot to handle? Problem arises
• Lighted on this sum up for a colour change
• 4 downed the figures up here in red and blue
• You get nothing but a cold chop from that
• Up with the figures 'til you have it in red and blue!
• Old dance
• It turns red in acid and blue in alkali