Is it safe if there is a small amount of rubbish/debris in the compost?

If you are saying you cleaned up the neighborhood of fallen leaves and got a few pieces of plastic, metal a few cigarettes...I would not worry. Compost the leaves adding green material (grass clippings) and carbohydrate food scraps.

The compost you purchase from a facility where people dump leaves, clippings all of the time will always have bits and pieces of man-made debris. Plastic will be with us forever, sigh. There is always pesticide residue in purchased compost as well. At least one knows that there isn't much pesticide residue unless the trees were sprayed. Not much one can do to hope for unmolested compost and you are doing the best thing by making your own having quite a bit more control.

Cigarette butts are not a problem in my opinion. The tobacco is a 'natural' product after all...The additive chemicals have already been smoked, inhaled and are in someone's lungs. (The word 'Natural' does not mean SAFE. The inherent nicotine in tobacco has one of the highest kill rates...it is termed LD50; 'Lethal Dose in half the population of test subjects, mice, rats). Nicotine has one of the LOWEST numbers of all chemicals. Meaning it is a very potent poison.

The filter is plastic stuff and will be around forever unless you pluck it out of the soil/mulch. Unless there is a whole ashtray of butts, no biggie. Paper will decompose eventually.

The material you need to worry about in your compost is feces from omnivores and carnivores (that includes us), meat and meat products as well as household chemicals. Urine is fine but I draw the line there if I want to use my compost for food crops.

You are doing a great service for your neighbors, showing them the value of those leaves. Such super stuff. One caveat! Are any of these leaves from walnut trees, Juglans ssp.?? Any debris from walnut trees should never be used in compost. Working with walnut as a carpenter means masks, gloves, sequestration from other projects and cleaning up all the sawdust because of the toxic chemicals this genus produces...

An excerpt from this 'gardening dude' about walnut leaves:

And what about making compost with the leaves? Dr. Roth told me he never puts ANY black walnut leaves in his compost pile; he saves them to use as a 'killing mulch' to get rid of unwanted plants! (VERY clever! And I'll add that the chipped uproots would be even more effective!) The experts at Ohio State say that well-shredded walnut leaves lose their plant-harming capability after a month of hot composting. But if you have a LOT of black walnut leaves going into your pile, they suggest you test the finished compost by planting some extra tomato seedlings in it before you use it on a larger scale. Juglone, they explain, is tomato Kryptonite!