Tahaarat

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?

Mazoor woman changing her liner for every salaah

Q: I consider myself a mazoor (excused person) due to chronic vaginal discharge. Nothing excessive but I have leaks especially during prayer. I wear panty liners to absorb the discharge. Sometimes theres a lot or just a few drops or even none (between prayer times). Example due to work I pray Zuhr at the end about 10 minutes before Asr. I still do a new wudu for Asr even though the time is very close. I do a new ablution for each prayer.

My question is, do I have to change the panty liner for each prayer? Or can I keep wearing the same one for 2 or 3 prayers?