[integrity]

I think the reason you don't spray it directly to the surface in the sun is the surface temperature causes the solvent to flash off before the polymers are spread. Too many in one spot would look like flashing. By putting the OID on the towel it spreads more evenly and won't flash as quick. If the paint is cool: you can do the towel or directly to the panel.

[Purplewidow]

everyone thinks they can put whatever they want on when it's hot outside in direct sunlight or in extreme humidity.. trust me don't qd or apply wax or cleaner fluid in these scenario's. your asking for hazing/streaking issues. same with washing in the direct sun and getting water spots unless you can run around the vehicle super fast to dry it. for the record DON'T APPLY QD'S OR WAX IN DIRECT SUNLIGHT!!!!!

[Peugeot]

Ya, that advice sounds sage. And "integrity's" explination makes sense. However, absent of direct sunlight, wouldn't it be a wash spraying directly vs on MF first? I mean, there's not gonna be a heat induced flash occuring, and that's what's essentially causing the streaking, no?

[Bence]

Smearing is the tendency of a protective sealant/wax film to be too mobile on the surface. This can cause a smeary, greasy, hazy appearance, show fingerprints or an oily look. Smearing is usually caused by over-deposition of (higher viscosity) active ingredients. It is key to use the correct amounts, otherwise you can buff it for hours and you'll just move the film around. Solution: use less.

Streaking is generally defined as marks/imperfections in the protective film of the sealant/wax that are basically immovable, or hard to move with simple rubbing. In extreme cases, streaking appears as swirl marks where the product was applied.
There are two main causes for streaking:
- The film-forming active ingredients cannot spread and level well.
- The film-forming active ingredients interfere with each other (or with previously applied products).
Allowing too little or too much drying time can have negative effects on the film. Sealants that are left to dry for too long may also cause difficulties. This is because after the solvent has evaporated, the remaining actives cannot be buffed to a smooth finish - especially if the materials have begun to cross-link and anchor to the surface - causing a non-uniform film.
If you have incompatibility issues, try to determine which previously applied product could have been the source of interference.