I bought the house I am in now over 20 years ago.
The man before me had had the roof done and the people who did it just let all the rubble and dust fall down on to the lost floor between the rafters.
I wanted to lay loft insulation (it had none) and I began to clear out this dust and rubble.
It was a horrible job, having to crawl around on my hands and knees in the loft, lifting all the dust and rubble up.
I had to wear a face mask all the time (I got through dozens of them)
I used an old vacuum cleaner to lift some of the dust, but had to keep going down to empty the bag.
Plus I had to sweep up the rubble with a dustpan and brush.
It was an awful job that took me weeks, on and off.
If you already have loft insulation then just board it over to save time and all the dust and mess.