Better just to get quality rechargeable AA and AAA cells like Eneloops that will last a really long time. One Eneloop AA cell down to 80% usable capacity per full charge approximately equals 1000 name brand alkaline AA cells in cumulative lifetime capacity potential. (This is assuming you're not recharging your alkaline cells, which is possible to an extent, but not a good idea.) A couple other nice things about Eneloops is that they don't self-discharge over time at a noticeable rate like some other rechargeable cells do, being able to hold up to about 75% of a full charge after 3 years, and they have a higher usable capacity per charge than alkalies do at higher drain rates.
Solar charging is an option, but ideally you need a charge controller of some sort that charges a battery when it isn't full and when the sun is out, and then that battery is used to charge other batteries, or function as a 5V USB power source for charging cell phones, or similar.
So anyway, what I'm saying is that the best way to not waste alkaline cells is to not get them in the first place. 