Yesterday i have burned big amount of old confidential papers (black and white, not glossy).
Now i am wondering if using these ashes will create any soil contamination.
Based on my own experience,it's not good that you're going to use that. It will be better if you'll use decayed organic matters like leaves or manure, used to improve soil structure and provide nutrients.
Shredded would have worked also, paper has more nutrients than ashes. Ultimately ashes from paper is the same as ashes from wood+ whatever is used in the processing like clay, soda, enzymes etc. My problem with using it in the garden is it has to be turned under, tends to blow around worse than just wood ashes, bieng flakier.
How alkaine is your soil?
Paper ash shouldn't be toxic, but it won't add much in the way of 'goodies'.
I put all my paper in the compost. It would have to be a pretty dedicated individual to poke around in there for my confidential info!
But I don't have 'critters' like you guys, and my mail's not particularly thrilling, let alone cofidential!
According to me you can use.
About all of what was in the wood that is left after pulping to make paper is the celulose fibers, nothing of the nutrients that the trees once contained. If the paper is clay coated there might be some added ti the paper but probably not much. I can find nothing that lists what, if any, nutrients might be left in the ash from burning paper but I'd suspect not much since the paper itself would not have much.
Newsprint, what newspapers are printed on may have more nutrients because the pulping process is different then that of the more commercials shhets.
My soil is more on acid site, so i was hoping that ashes will be not so bad. I dumped them in compost.
When I consider the volume of ashes left after you burn paper - i.e. minimal and very hard to contain - I choose to shred paper and add it to compost pile to help balance the wet ingridients
I then use ashes from wood burn pile to add directly to the soil of raised beds