Old Oil Paint - Stuck screw cap

The paint I borrowed from the teacher after painting class sucks. I mean... She says it's expensive and heaitated to let me take it but the truth is not one tube I can open, noone took care of it soooo... Let's see if hot water makes a difference since I already spoiled black on the table cloth my child bought 🤐

Oil paint contains a lot of pigment. I grabbed in red and you can guess what happened next... 😖
Red, red, red and no turpetine so I took the bottle with sunflower oil and rubbed my hands with it (any oil will do the trick and you can save your brushes in oil as well till you start painting again...). I rubbed with oil, dishwas deteegent (or use soap)... More red but after a second wash my hands were clean. Wearing gloves is a better option by the way.

And if you wonder... This is what is left from black. The tube thorn and I used it to paint three black background with the idea to paint faster (wet in wet) but in the past days I didn't come to continuing it so... It must be today or tomorrow since the paint should be returned on Wednesday.

What I dpn't understand: why saying it's expemsive and hesitate if no one uses it, the paint is old and no one cleans the tubes?

I taped all three on a big panel to drag it out (it smells) but also to make an uniform background (black is black since there are no different colours available yet).

_{7.12.25
I let you know if it works. It's a pity to throw it away.}