here u go. u dont need raw watermellon, just get the usual riped watermellon. rato bhag jati chai katera khane ani baki rakeho bokra ra seto bag le khalpi banaune, ali ali rato bhag baki rakhne. bokra lai chai kakra lai jastai knife le khaurine(hope u got), dont peel it. ani tukra , tukra banaara katne. u know how they cut khalpi right? serrated cutting, in this case bokra pati. Now just leave in sun for 1/2 hrs. then add salt, turmeric, mustard powder, red chilli, ali ali jeera dhaniya ko dhulo ani tori ko tel.u can add green chillies if u want, just put it in the bottle n leave in sun for few days. would taste almost like khalpi. i ve done this several time . this is an excellent recipe out of something u would never use. just try n let me know. bye