How to remove the sins every day, which we commit ?

The Pratah Sandhya (morning twilight) is

related with the Sun God.

By standing in the morning twilight,

 if we enchant the mantra or sloka  or

 do the japa , all the yesterday’s sins will be eliminated.

Like wise, in the evening twilight  (Sayam Sandhya),

sitting at one place and enchant the mantra

 or do the japa , the sins which we

committed (without intentionally) on that day will be removed.

 In the evening twilight, for Sayam Sandhyavandanam,

 we should have to do  the Gayatri mantra

 japa till the stars brightly shine.

Even on the fasting  days, some  people

follow the same traditional custom of

that  Ubhaya Sandhya vandanam with out fail. 

What are the results for meritorious deeds and also for charity ?

There is an altruistic view (paramaardham)  behind

 those words of meritorious deeds and offering charity.

Here the meaning of Punyam  is meritorious deeds.

 Means if any maiden or woman worship the God

 or Goddess with the superior flowers ,

then a very good person (virtuous person)

 will be obtained as her  husband.

The Daanam means charity.

If any woman offer the charities with

compassion to others, then she will

beget the very good progeny.

So, such a traditional customs which

 are derived from our sacred sastras,

  are well known to all and

also those are practiced with belief.