Impurities

Lizard droppings on a wall

Q: As we all know that almost all houses have lizards. My question is: 

1. Lizard's dropping is found on the wall and it has dried. If we paint the wall and the brush touches the impurity, does it make all the wall with new paint impure? 

2. If this wall with new paint dries and someone with wet hand touches it, but the traces of color is not visible, will his hand be pure?

Are the splashes of water over non-flowing blood impure?

Q: If you pour water (flowing water) over a wound that is still bleeding a little when checked with tissue but the water falling off is clear (no detectable traces of blood) even though logically there would technically be blood in it, is that water and its splashes impure? Are the areas on your hand that are now wet around the wound considered impure?

Killing a spider on one's carpet

Q: Spiders don’t have blood in their circulatory system. They have something else called haemolymph. Is this impure because a few weeks ago I squashed a spider on my carpet in my bedroom, so does that mean this carpet is impure? I’ve also walked all over this carpet with wet feet after wudu sometimes.