I dyed a navy linen skirt which had got very faded, and in the same lot some M&S very light beige cotton trousers which had a stain that wouldn't come out - I dyed them both navy.
However although the fabric of the trousers was cotton, the stitching was all evidently polyester, so that stayed white.
Luckily the effect was such that it looked intentional, but it's something to be aware of.
I used Dylon's machine dye and was very pleased.
To obliterate your address on packaging
Tales about "stingy" guests and hosts.
sticky labels on apples - remove before washing!