Buying and selling shares

Q: If we interpret various Fataawa then it seems we can purchase shares and then sell them. But some people say that if you purchase the shares speculating that they will go up and sell within few minutes or after an hour or after some days then it is gambling. They say that the sole purpose of share buying should be the partnership of the company. If we are buying shares in anticipation of getting higher price afterwards, it is haraam. According to some muftis the sole purpose of buying the shares should be the partnership in the company and not trading. My question is can I buy the shares of a permissible company and then sell it when the value goes up?

Early settlement discount

Q: We have customers who buy on credit. Is it permissible for us to tell them that we will give them a discount if they pay before the due date? For example, the customer purchases goods worth R100 000 on a three month credit basis. The customer is told, “If you pay within one month, you will receive a 10% discount”. Is this permissible? 

Stickiness remaining after removing a plaster

Q: Due to a small tiny cut on my left knuckle middle finger I put a plaster on it, I removed the plaster afterwards and washed my hands but realised later after that there was still some residue of the plaster stickiness/glue left so if you rubbed it off it would form like a sticky rubber effect. Because I may have washed impure hands afterwards whilst the stickiness was there and not realising and then wiped them with a towel, I am concerned impurity may have been spread or would be pure as I initially did wash my hands but did not realise the stickiness was still there. I am a waswas sufferer and I am getting better everyday with the help of the almighty therefore I am always very concerned on purity as I always think I am spreading impurity everywhere.