If so, even the delicate setting in a dryer may (possibly) shrink your afghan, although it might straighten itself out again if placed on a bed and stretched out a bit later. If it was made with acrylic or a combination of natural/acrylic - the delicate setting would probably be ok. That's just my experience with my own afghans I've made.

(I usually hang those things I've made with all natural fibers, though it's a bit harder with a large afghan. Those, I hang outside to dry in a not too sunny spot).

on a delicate cycle and it will come out just fine. If it is a natural fiber, you need to dry it naturally. You can drape it across a clothesline or put it on a drying rack outside. You might want to consult with a professional cleaner to see if you can figure out what type of yarn your mother used. If it is wool, you def. need to stay away from a commercial dryer at the laundromat, or you might just wind up with a very thick baby blanket.

I'd recommend washing the item in cold water, using the Delicate Cycle, and using the Delicate Cycle for the dryer, also. Be sure to remove the item from dryer promptly, because the yarn of the item could start to pill up if it remains in the dryer too long. Here's hoping I've been of some help here. All the best.

An afghan made years ago with wool yarn would probably not feel so soft. Wool yarn needs to be washed in cold water and dried flat.

Years ago, my boss (in textiles) explained why wool shrinks. Wool yarn has protruding hooks on the fibers that lock together when wet. Acrylic yarn is smooth, with no protruding hooks.

If there is a loose bit of yarn that you can cut off, you could test that.

When you burn a piece of yarn that is wool, it doesn't light up easily. It smells like burning hair and leaves only ash.
If the yarn is acrylic and you burn it, it lights easily and melts into a hard, black lump.

If it's wool, don't use the drier. If it's acrylic, you can use the drier on a low heat setting.

Go there with it and ask them for advice. They will pretty much instantly know what kind of yarn it is and how you should care for it.

For what it's worth, my washer has a hand wash setting, and I'd probably put it in that, cold water of course, and then it can be tumbled dry.

There were a number of good decent yarn shops in my general area, which either went out of business, or moved to places that are farther away from where I live. I've frequently been getting yarns online.

Just get some woolite or other wool wash, fill your washer about 1/2 way with cold/lukewarm water, add some of the woolite (the pkg will tell you how much), place the item in the water, and LET IT SIT for about 15-20 minutes. make sure you don't agitate it! then, set it on spin. when it's done, hang it to dry somewhere. i wouldn't use the dryer at all. oftentimes, even if it's safe to dry it, all the little "ends" that were woven in by the maker, will pop out. it's not a pretty sight. good luck!

you can go outside and do a burn test to determine whether the fibers are animal, vegetable (like cotton) or synthetic.

http://www.fiber-images.com/Free_Things/Reference_Charts/free_reference_charts_fiber_content_guide.html

You can put it into the bathtub with cool water and wool safe detergent like Eucalan (available at craft stores that sell woolen yarn) or supermarket Woolite. They will both felt wool if you agitate the water, so just lay the Afghan into it and let it soak for a couple of hours. Rinse twice in plain room temperature water, roll in towels to squeeze the bulk of the water out, and dry flat away from direct sunlight. On newspaper in a carport is ideal, the car won't mind being outside and you don't lose floor space.

Chances are good that it's acrylic. Those you can throw into the washer and dry in the dryer, it's what I knit my Afghans with just for that reason. I do find that using extra liquid softener keeps it from feeling like plastic. Since everything else in here reeks of sheep and wool, I've fooled a lot of people with them if they're super soft.

I sell Mexican Collectibles and from time to time I come across old serapes and woven items. I have found that the cleaners is my best bet. If you are wanting to keep the item as a momento. I would advise the cleaners. They will know what to do and the item comes back nice and clean.

Dirt and dust are murder on old textiles, they are like grit and rub away at the thread which causes the thread to weaken and "pop" which is the start of a hole.

If there's a loose thread you could do a burn test. Singe the end. If it turns to ash, it's an animal fiber. If it melts, it's usually acrylic. In any case, you can't go wrong with a cool wash, lay out flat to dry. But try not to agitate. If necessary, use the washing machine to spin the excess water out of it. Wet afghans can be horribly heavy.