The stuff I use can be shifted with the careful application of a fingernail. Don't go near it with anything metal. I know of no solvent which wouldn't also damage the canopy.
If the smears are very thin try rubbing them into a ball with the fleshy part of your thumb, like you used to do to shift that 'orrible sticky stuff left on your skin when you pulled off an Elastoplast! Works for me – it's just not something I share with everybody….
Must be really strong stuff. I use DeLuxe Materials' version, which does the job but may not be the world's strongest, and apply it with either a fine paint-brush or a hypodermic syringe with a blunt needle. These are available from a well-known Internet auction site.