Homemade row cover materials

The title pretty much says it. What are some materials you can reuse for decent row covers to keep the frost off? I've heard of old towels

I have some really ugly polyester yardages from the thrift store that I've used for years to cover certain things.  It never dies.  It also doesn't let any light in so has to be removed during the day.

I've used old cotton sheets and have thought that light weight curtains would work well.

All of these are too heavy to lay right on the plants though.  we have a couple rabbit wire low tunnels that hold the cloth up off the foliage.

Did you have a plant or tree in particular in mind or just in general?

I tried that 'garden fleece' stuff for a couple years and ended up giving it away...it got holes in it so easily.

In a pinch, we've used dirty laundry, for an early fall frost that was a one-night event. It's going to get washed anyway and works as well as any other cloth.

Just for general use, like for tomato transplants. I always jump the gun on seed starting and end up with large plants before I'm really supposed to. Oops

Bedsheets seem to work well.

If you need something you can leave in place, there are a lot of white fabrics that let light through, that are pretty cheap by the yard.

I got two 30' by 4' cloth at a garage sale for 50 cents !
At garage sales, think of gardening and so many products start to look ridiculously cheap and useful!

we have garden blankets which basically live outside. they are usually wool blankets which will easily dry out and they seem to handle being outside most of the year. we do have to remove them during the day, however i have kept them on over wintering brassicas for a whole month with no ill effect.

sometimes they are old wool blankets or an old wool blanket which got some funk to it, like mould.

These have been found for free at our local free store. however i imagine buying them at second hand stores would also work if the price was right.

Are average old cotton sheets or tablecloths the right amount of shade for let's say lettuce? Is rain going to drip through it, into one spot or distribute evenly through misting? Does it matter?

When I use sheets to cover my chicken tractor, rain drizzle drips in one spot.  It may pool in that spot. But you could always water other dry areas.
I think it might be too dark for lettuce unless it is a thin, light color cloth.  But I'm in Texas.  I might use them for excluding butterflies that lay caterpillar eggs on lettuce, or to keep the lettuce a little cooler.  Maybe spraying water on the cloth would keep that area cooler due to evaporation. But it would be a lot of spraying.