This blog is courtesy of #Intern Matt#, and I think it kicks ass:
The bigger location battery powered strobes kick out 1200w/s of power, recycle quickly, and produce beautiful light… but buying accessories for these packs adds up quick… and can be a serious PITA to keep from getting damaged. So if you are cheap but handy, here is a quick modification that will save some dough without compromising on you light shaping needs. This modification is done with an Elinchrom set up, but can easily work for others such as Profoto.
Products in Demonstration: Alien Bee 11” long Throw Reflector ($29.95 [alienbees.com]). Elinchrom Umbrella Wide Reflector 16cm ($44.95 [BHphotovideo.com])
Product you’re Replacing with the Modficiation: Elinchrom High Performance 10” Reflector ($124.95 [adorama.com]). Profoto Wide Zoom Reflector ($419.95 [bhphotovideo.com])
Tools you will need: tin snips, duct tape, stick and velcro 
Step One: Cut a hole in the box…. Just kidding. The first step is the most important. You have to judge where you’re going to cut the Alien Bee reflector. If you cut too much off, your smaller reflector will just pass through the hole, so judge correctly. It’s ok if you don’t cut enough off, because you can always take more. It’s better to be conservative.
Step Two: Put duct tape around the snipped edge to avoid cuts.
Step Three: Attach the velcro to both reflectors. The smaller reflector should 
have the velcro on the outside, the larger one will have it on the inside.
Pros: For each reflector, you save around $50 with Elinchrom and about $300! with Profoto. Reflectors detach making for easy storage while traveling, you have an umbrella reflector handy, and when your Long Throw gets smashed traveling like it always does… you wont feel bad shelling out $30 for a new one.
Cons: Depending on level of laziness, it takes a small amount of effort to create.
